If after turning on the power computer won't boot, this can be due to several reasons.

■ If the message Invalid system disk appears on the screen at the initial boot stage. Replace the disk, and then press any key and you cannot do work from home, check if a floppy disk is inserted in your computer's floppy drive. If a floppy disk is present in the drive, remove it, then press the Reset button on the front panel of the system unit, or turn off the computer's power and turn it on again.

■ The computer may not boot if the boot process of the operating system stops at any stage, press the Reset button on the front panel system unit or turn off the power of the computer and turn it on again, then press the F8 key at the initial stage of rebooting the system. A menu will appear on the screen, in which you should select the Safe Mode item using the cursor keys in Windows 2000 / XP or by sequentially pressing the 3 and Enter keys in Windows 98 / Millennium Edition. After Windows finishes booting in crash protection mode, perform a disk check. In Windows 98 / Millennium Edition, to do this, select Start> Programs> Accessories> System Tools> Check Disk, and then click the Run button in the opened Disk Checker window. In Windows 2000 / XP, open the My Computer window, right-click on the icon of the drive on which Windows is installed (most often it is the C drive :), in the menu that opens, select Properties. By clicking in the upper part of the window that appears on the screen, go to the Service tab, click the Run check button, check the Automatically fix system errors and Install bad sectors checkboxes, and then click the Start button. Most likely, Windows will prompt you to perform a check the next time the system boots, accept this offer by clicking the Yes button. Reboot your computer.

If the computer did not boot, then after booting the operating system in safe mode (to select this mode, press the F8 key at the initial stage of Windows startup) in Windows Millennium Edition / 2000 / XP, you can use the System Restore utility. To do this, select Start> Programs> Accessories> System Tools> System Restore for Windows Millennium Edition / 2000 or Start> All Programs> Accessories> System Tools> System Restore for Windows XP. In the right part of the System Restore window that opens, set the switch to Restore your computer to an earlier point in time (Restoring your computer to an earlier state) and click the Next button. On the left side of the next window, you will see an image of the calendar, in the table of which in bold the dates on which Windows automatically created a "snapshot" of the system are highlighted - it is to the state of one of these days that you can restore Windows using this program. These "snapshots" are called system restore points. You can switch months in the calendar by clicking on the buttons with the right and left arrows. After selecting the desired month, click on the date when the desired restore point was created. In the field to the right, you will see the time it was created and a short text comment. You can scroll through the list of restore points by clicking the right and left arrow buttons above the description of the restore points. After selecting the desired restore point, click the Next button. System Restore will show you information about the selected restore point. Click the Next button to start System Restore. Within a few seconds, System Restore reads all the information it needs from the disk, after which the computer will restart. After the completion of the resuscitation process, Windows will boot in normal mode with fully restored settings. System Restore does not mean that after you restart your computer, you will lose any documents or e-mails you have prepared recently, but programs installed after the date the restore point was created may not start and you will need to reinstall them again.
If, when you turn on the power of the computer from the system unit, you hear beeps consisting of a series of long or short beeps (and the image on the monitor screen may disappear), this means a hardware failure - most likely, computer won't boot because something in the computer is out of order. Contact a computer repair technician.

As a service center engineer, I often hear complaints from customers that the computer won't start or boot. This is how they describe various problems - from problems with switching on to a violation of loading the operating system. But to be more precise, "does not start" should be understood as does not turn on, does not initialize or does not work, while "does not boot" should mean exactly problems with the system boot.

Let's look at examples of specific symptoms of why the computer does not start.

No response to pressing the power button

Causes

• There is no voltage in the mains, the power cord is damaged or the power supply unit is out of order.
• Power button damaged.
• There is no electrical contact in the power connectors.
• The power management chip is out of order.
• Internal power supply damaged (on laptops).
• The chipset is out of order.
• BIOS is corrupted.

What to do?

• Make sure there is voltage in the mains. Check if the power supply is turned on and the cable is securely connected to it. If possible, test the computer with a different power supply.
• To test the button, disconnect the wires from the Power Switch contacts (ON, PWR_ON, PC_ON) on the motherboard and close the contacts with a screwdriver. If the PC turns on normally, the button is to blame.
• Reset the BIOS by removing the CMOS battery and short-circuiting the socket pins. Or using the Clear CMOS jumper (button) (other names - CLRTC, CRTC, CL_CMOS, CCMOS).

The computer turns on (fans are running), but nothing appears on the screen

Causes

• The processor is defective or there is a problem in its power system.
• The north bridge is out of order.
• Defective strips, slots or power supply of RAM (random access memory).
• The BIOS firmware has crashed.

What to do?

• Make sure the processor is not damaged and its cooling system is properly connected.
• Check if the additional 4-pin connector near the CPU power supply is connected.
• Check the operation of the RAM strips in different slots, try replacing them with known good ones.
• Reset BIOS settings.

Computer shuts down or restarts during startup

Causes

• Overheating of the processor or main components of the system board.
• Failure (short circuit) of one of the computer devices.
• The voltage levels on the motherboard are out of range.
• BIOS problems.

What to do?

• Clean the cooling system from contamination. Refresh the thermal paste layer on the processor.
• Disconnect all devices that are not necessary for starting the computer: peripherals, expansion cards (sound, network, etc.), optical drive, everything connected to USB (except for the keyboard), RAM (except for one bracket), hard drives, except for the system ... If the PC starts up, one of the disabled devices is to blame.
• Reset BIOS settings.

Operating system loading does not start

Causes

• The system hard drive has failed, is not properly connected, or is not receiving power.
• Chipset (South Bridge) problems.
• BIOS problems.
• Corrupted MBR or operating system boot files.

What to do?

• Make sure that HDD correctly connected, operational and receiving power. Check if it is detected in BIOS and visible when booting from other media.
• Reset BIOS settings.

If all else fails, and also if the problem with switching on occurs on the laptop, contact the service.

Let's talk about the problems associated with the Windows XP operating system in more detail.

Why might Windows XP fail to start?

There are many reasons why Win XP won't load. These include damaged or missing boot files, registry changes, incorrect boot.ini configuration file settings, MBR (Master Boot Record) corruption, and sometimes a combination of these factors. These problems arise most often due to the following:

• viral activity, especially associated with blocking the MBR and Windows desktop, as well as due to unsuccessful attempts to cure such viruses;
• errors when creating a configuration with loading multiple operating systems;
• surface defects of the hard disk;
• power outages that damage Win files during read and write processes.

For a better understanding of the causes of Win XP boot failures, let's briefly analyze how this process goes.

How to boot a computer running Windows XP

Before the system stages of turning on the PC - receiving the Power Good signal by the motherboard, initializing the devices and starting the BIOS code execution, we will not consider, since the problems at this stage are related to hardware. The beginning of the start of Windows will be considered the execution of the MBR boot code, which transfers control to the BIOS. So.

• The MBR finds the active partition in the table and transfers control to the boot code from its first sector (Boot Sector).
• When executed, the boot sector code transfers control to the NTLDR file, the Windows XP boot loader.
• NTLDR puts the processor into 32-bit mode and checks if a hibernation image (hiberfil.sys file) is saved on the hard disk. If there is such an image, it loads it, if not, it reads information from the Boot.INI - the boot configuration file.
• If multiple copies of Win are installed on the computer, a menu is displayed from which the user can choose which system to boot.

• After selecting the system, the ntdetect.com file is launched, which determines the hardware configuration of the current boot.
• Next, the files ntoskrnl.exe (Windows XP kernel) and Hal.dll (Hardware Abstraction Layer) are loaded - an intermediary between the PC hardware and the Win kernel.
• The last task of NTLDR is to start the drivers marked as bootable in the registry and transfer control to the kernel code. At the same time, the equipment is initialized, the interrupt controller and the I / O system are turned on.
• The Windows XP kernel starts the session manager - Smss.exe, which creates the user environment, the graphics subsystem - Win32k.sys, the client-server execution subsystem Csrss.exe, the Win logon program - Winlogon.exe, the authentication service - Lsass.exe, and Services.exe - Service Control Manager.
• This is followed by the launch of the welcome screen - LogonUI.exe and the user logon program in Windows - Userinit.exe.
• Next, the explorer (Win shell) - Explorer.exe is launched, the desktop appears on the screen and the system goes into standby mode for user commands.

How to restore boot Windows XP

Win boot failure can occur at any of the listed stages. Knowing what follows what, it is easier to understand the reasons that disrupt the launch of the system.

Master boot record (MBR) repair

In case of damage, the MBR is interrupted at the very beginning, almost immediately after turning on the computer. It is manifested by the fact that a message is displayed on the screen:

• Missing Operating System - operating system not found;
• Invalid Partition Table - invalid (defective) partition table;
• Error Loading Operating System - error loading the operating system.

Or nothing is displayed.

If the MBR is damaged, both the boot code and the partition table can be damaged. To recover the MBR code, you need to start the computer from the Windows XP installation disc and enter the recovery console. For this:

• put the installation disc into the drive and start booting, when you see the message "You are welcomed by the installation program", press the R (restore) key;

• to work in the console, specify the serial number of Win XP where you want to log in. If you have one system, press 1;
• enter the administrator password;
• enter command fixmbr and press Enter - the boot code will be overwritten;
• to exit the console, enter the command exit.

The partition table cannot be fixed by Win's own tools. To do this, you have to use third-party programs. One of these is the utility TestDisk, does an excellent job with this task.

Recovering the boot sector and NTLDR boot loader

Boot sector code corruption has the same symptoms as MBR corruption, and error messages can be as follows:

• NTLDR is missing - NTLDR loader was not found;
• And disk read error occurred - a disk read error occurred;
• NTLDR is compressed - NTLDR loader is compressed (not unzipped).

To solve this problem, you will need the Recovery Console again, where you will need to run the command fixboot.

The same messages may appear if there is no NTLDR loader in the Windows XP root directory. A copy of this file transferred from another computer running Windows XP or from an installation disc will help to fix the situation.

Boot Configuration Setting (Boot.INI)

If the Boot.INI boot configuration file contains errors, Win XP will also be unable to start, since NTLDR will not know what to boot with what parameters. The system notifies about this problem with the following messages:

• Check boot path and disk hardware - check the disk and the path to the boot partition;
• Could not read from selected boot disk - could not read data from the selected boot disk;
• Windows could not start because of a computer disk hardware configuration problem - Windows startup failed due to a disk configuration error.

The Recovery Console will help you out of the situation again. Run the command: bootcfg / rebuild- it restores the default boot.INI records. In the course of its work, all partitions of the hard disk are checked for installed copies of Win. If systems are found, records about them are added to the configuration file, and the user can confirm or deny adding the system to the boot list. In this way, it is possible to restore the launch of several copies of Windows at once.

Registry repair

Another reason XP does not load is registry corruption, especially the System keys, which contain information about starting drivers, and Software, which contains boot control parameters.

To "roll back" these two partitions to the state at the time of system installation, start the recovery console and run the commands:

rename c: windowssystem32configsystem system.old

rename c: windowssystem32configsoftware software.old

copy c: windowsrepairsystem c: windowssystem32configsystem

copy c: windowsrepairsoftware c: windowssystem32configsoftware

In the same way, you can restore other Win registry keys: Defoult, Security and Sum.

Recovery of boot files

You already know why the files responsible for Windows startup XP lose functionality. Win in such cases is loaded almost to the end, but at some point it goes into reboot or ends with BSoD. So, error 0xC000021a (fatal system error) indicates the absence or damage of Winlogon.exe or Csrss.exe. Problems with other files may not be accompanied by messages, but only show up as a black screen during the boot process.

If you know which files are missing, you can transfer them from another similar system or from the distribution disk - from the i386 folder. To do this, the computer is also booted from the Recovery Console, where the commands for copying and unpacking files from the storage are executed. So, the command expand d: i386userinit.ex_ c: windowssystem32 will unpack and copy to a folder system32 file userinit.exe where d: is the installation disk.

If you do not know, because of what files, installation of the system in recovery mode will help. System files will be overwritten, while programs, settings, and user data will remain unchanged.

• Start your computer from the installation disc. When the "Welcome to the program ..." window appears, continue with the installation by pressing Enter.

• In the course of further work, the program will scan the disks and if it finds a copy of Windows XP on them, it will offer to restore. To do this, select it in the list and press "R".

• After the reboot, several more stages will pass, where user participation is required. Including - entering the serial number.

• At the end of the operation, the files will be overwritten, and if the reason why Windows did not boot was in them, the system will restore its work.

Moreover, it is quite expensive, but it stopped loading for no apparent reason.

It is good if it is possible to quickly deliver it to the service, but in a number of situations you have to fix the malfunction on your own.

Of course, without a detailed diagnosis, it is impossible to find out the true cause, as well as to give universal advice, but several of the most common reasons can be considered.

What to do if your computer won't boot

First you need to find out at what stage the computer "hangs", at the stage of self-testing, or when Windows has already started loading.

In the event that the Windows logo appears on the screen, after which the download stops, the problem is guaranteed in the damaged operating system, with the computer hardware most likely everything is in order.

Sometimes loading the last known good configuration helps. To do this, immediately after turning on the computer and giving the BIOS a signal about the successful passage of self-test (one short), you must start pressing the F8 button. In the menu that appears, select "Load Last Known Good Configuration". If the system then starts up, the problem will be resolved.

If the Windows logo does not appear, but the computer passes the test, you can try to boot from external media, for example, from a bootable Windows system disk. If the download went well, the problem is most likely in the operating system, after reinstallation everything should work fine.

If the computer stops starting during the self-test phase, the problem lies in the hardware. It is necessary to listen to the signals given by BIOS with the help of the "buzzer".

Depending on the signals supplied, you can try to determine the cause of the failure:

• One long, three short - video card malfunction. The first thing to try is to pull out and insert the video card into place, check the connection of additional power cables to it, if any. If this does not help, you will have to contact the service.
• Three long ones are a memory error. Remove one of the modules and try to start the computer again. Remove both memory modules, if there are two, and try to insert them again in the same slots, or in other free memory slots, if the motherboard provides for installation in all slots of the same type of memory.
• One long and one short, repetitive short, continuous - malfunction motherboard or processor. We'll have to contact the service.

On some early motherboards, clearing the BIOS can help. Find on the board a jumper (jumper), consisting of three pins, under which is written Clear CMOS. Move the jumper installed on it to a different position (for example, if it is now installed on the first and second contacts, move it to the second and third) for a minute, and then return it back. Try to start the system.

Sometimes even such a method as removing the network cable from the power supply unit, wait a minute and plug it back in helps. This is due to the operation of the power supply protection system against voltage surges.

It would seem that the computer boot process has been studied by us to the smallest detail: button - BIOS - operating system - login ... Have you ever thought about what is actually happening inside your computer at this time? Can you tell us step by step how the computer works? I’m sure not. Therefore, today we will conduct a short educational program - we will talk about how the computer actually boots.

This article discusses Windows work XP, in other systems, the process is naturally somewhat different.

The power switch turns on.
The power supply performs a self-test. When all electrical parameters Normally, the PSU sends a Power Good signal to the processor. The time between power-up and signal disappearance is usually 0.1-0.5 seconds.

The microprocessor timer receives a Power Good signal.
On receipt of this signal, the timer stops sending the Reset signal to the processor, allowing it to turn on.

The CPU starts executing the ROM BIOS code.
The processor loads the ROM BIOS starting from the address FFFF: 0000. At this address, only the transition to the address of the real BIOS ROM code is registered.

The system performs an initial hardware test.
Each error encountered at this stage is reported by certain sound codes (in the past by beeping, now it is probably more modern - by voice), since the video system has not yet been initialized.

The BIOS looks for adapters that may require their BIOS to boot.
The most typical case in this case is a video card. The boot routine scans the memory from C000: 0000 to C780: 0000 to search for the video ROM. This loads the systems of all adapters.

The ROM BIOS checks to shut it down or reboot.
Procedure two bytes at address 0000: 0472. Any value other than 1234h indicates a cold start.

If this is enabling the ROM the BIOS runs a full POST (Power On Self Test). If this is a reboot, then the memory check is excluded from the POST procedure.
The POST procedure can be divided into three components:

• The video test initializes the video adapter, tests the card and video memory, shows the configuration or errors that have occurred.
• BIOS identification shows firmware version, manufacturer and date.
• The memory test checks the memory chips and calculates the size of the installed memory.

Errors that may arise during the POST check can be divided into fatal and not very good :). In the second case, they are shown on the screen, but allow you to continue the boot process. It is clear that in the first case, the boot process stops, which is usually accompanied by a series of beep codes.

BIOS reads configuration information from CMOS.
A small area of ​​memory (64 bytes) is powered by a battery on the motherboard. The most important thing for loading in it is the order in which the drives should be polled, which of them should be the first - a floppy drive, CD-ROM or hard drive.

If the first is the hard drive, the BIOS checks the very first sector of the drive for a Master Boot Record (MBR). The Boot Record in the first sector is checked for the drive.
Master Boot Record - first sector on cylinder 0, 0 head, 512 bytes in size. If it is found, it is loaded into memory at the address 0000: 7C00, then it is checked for the correct signature - the last two bytes should be 55AAh. The absence of the MBR or these check bytes stops the boot process and issues a warning. The MBR itself consists of two parts - the partition loader (or Boot loader), the program that takes control when booting from this hard disk; partition table (partitions), which contains information about logical drives available on the hard disk.

The correct MBR record is written to memory and control is transferred to its code.
The process of installing several operating systems on one computer usually replaces the original loader with its own program, which allows you to choose from which disk to boot the rest of the boot.

Next, Boot Loader checks the partition table in search of an active one. The bootloader then looks for a Boot Record on the very first sector of the partition.
V this case Boot Record is another 512 bytes - a table with a description of the partition (the number of bytes in the sector, the number of sectors in the cluster, etc.) and the transition to the first file of the operating system (IO.SYS in DOS).

Operating system

Control is transferred to the operating system. How does it work, how does the download process go?

Boot Record is checked for correctness and if the code is valid then the boot sector code is executed as a program.
Booting Windows XP is controlled by the NTLDR file located in the root directory of the system partition. NTLDR works in four steps:

1. Initial loading phase
2. System selection
3. Determination of iron
4. Choice of configuration

In the initial phase, NTLDR switches the processor to protected mode. It then loads the appropriate file system driver to work with files for any file system supported by XP.
If anyone has forgotten, then our favorite OS can work with FAT-16, FAT-32 and NTFS.

If there is BOOT.INI in the root directory, then its contents are loaded into memory. If it contains entries about more than one operating system, NTLDR stops working - displays a menu with a choice and waits for user input certain period time.
If there is no such file, NTLDR continues booting from the first partition of the first disk, usually C: \.

If during the selection process the user has selected Windows NT, 2000 or XP, then pressing F8 and showing the corresponding menu with boot options is checked.
After each successful boot, XP creates a copy of the current combination of drivers and system settings known as Last Known Good Configuration. This collection can be used to boot if a new device has corrupted the operating system.

If the selected operating system is XP, then NTLDR finds and loads the DOS program NTDETECT.COM to determine the hardware installed in the computer.
NTDETECT.COM builds a list of components, which is then used in the HARDWARE key of the HKEY_LOCAL_MACHINE branch of the registry.

If the computer has more than one hardware profile, the program stops from the configuration selection menu.

After choosing the configuration, NTLDR starts loading the XP kernel (NTOSKRNK.EXE).
During the kernel boot process (but before initialization) NTLDR remains the main control of the computer. The screen is cleared and a white rectangle animation is shown at the bottom. In addition to the kernel, the Hardware Abstraction Layer (HAL.DLL) is also loaded so that the kernel can abstract itself from the hardware. Both files are located in the System32 directory.

NTLDR loads device drivers marked bootable. Having loaded them NTLDR transfers control of the computer further.
Each driver has a key at HKEY_LOCAL_MACHINE \ SYSTEM \ Services. If the Start value is equal to SERVICE_BOOT_START, then the device is considered bootable. For each such device, a dot is printed on the screen.

NTOSKRNL goes through two phases during the boot process - the so-called phase 0 and phase 1. The first phase initializes only that part of the microkernel and executive subsystems that are required for the main services to work and continue the boot. At this stage, the screen shows graphic screen with a status bar.
XP disables interrupts during phase 0 and enables them only before phase 1. HAL is called to prepare the interrupt controller. Memory Manager, Object Manager, Security Reference Monitor, and Process Manager are initialized. Phase 1 begins when the HAL prepares the system to handle device interrupts. If more than one processor is installed on the computer, they are initialized. All executive subsystems are reinitialized in the following order:

1. Object Manager
2. Executive
3. Microkernel
4. Security Reference Monitor
5. Memory manager
6. Cache Manager
7. I / O Manager
8. Process Manager

I / O Manager initialization starts the process of loading all system drivers. From the moment where NTLDR stopped, the drivers are loaded by priority.
Failure to load the driver can force XP to reboot and try to restore the Last Known Good Configuration.

The final task of Phase 1 of kernel initialization is to start the Session Manager Subsystem (SMSS). The subsystem is responsible for creating a user environment that provides the NT interface.
SMSS operates in user mode, but unlike other applications, SMSS is considered a trusted part of the operating system and a "native" application (uses only executive functions), which allows it to start the graphics subsystem and login.

SMSS loads win32k.sys, the graphics subsystem.
The driver switches the computer to graphics mode, SMSS starts all services that should automatically start at startup. If all devices and services have started successfully, the boot process is considered successful and the Last Known Good Configuration is created.

The download process is not considered complete until the user is logged into the system. The process is initialized by the WINLOGON.EXE file, launched as a service and supported Local Security Authority (LSASS.EXE), which shows the login dialog.
This dialog box appears approximately when the Services Subsystem starts the network service.

If you are faced with the problem that the operating room Windows system XP does not load, the first step is to find out the nature of the breakdown.

There are two variants of the problem:

1. Software error due to software malfunction.
2. A hardware error caused by the failure of a specific part.

1. The computer responds, but does not boot

You pressed the Power button, and nothing is displayed on the monitor, but the cooler is working and the lights come on? Most likely, the monitor is not connected correctly or a hardware error has occurred. What to do if the matter is still in the hardware part?

Alternatively, contact has disappeared somewhere in your PC due to clogging with dust. Then you should do the following:

1. Unscrew the cover from the system unit and remove the video adapter and RAM.
2. Carefully remove dust on the parts and the system unit itself.
3. Thoroughly wipe the contacts of the video adapter and RAM.
4. Put all the parts back and check if the computer works.

If after the steps taken, the computer does not turn on and Windows XP does not boot, you will need to find the part that is out of order. This can be easily done using the BIOS ( basic system input-output). The main thing is to know which version is installed on the computer.

Every time the PC boots, it is checked using the BIOS. If any failure occurs during the test, the computer emits a sound, by the type of which you can find out the cause of the failure. You can find out about what kind of breakdown a certain sound signal says from the BIOS signal table.

If you do not know what version of BIOS you have, then you will have to suffer. You will need to change your parts one by one to others (borrowed from someone) until it becomes clear which one is inoperative. Is this option not feasible for you? Then it only remained to turn to specialists.

2. The computer does not respond at all

If you press the Power button, but the computer does not respond (the cooler does not make noise, the lights do not light up), you should immediately check if the computer is connected correctly. To do this, make sure that the switch on the back of the system unit is turned on and carefully examine the power cables.

If everything is connected correctly, then most likely the power supply has broken. If you have never dealt with electrical appliances, it will be quite difficult to eliminate such a breakdown yourself. Still, it would be nice to borrow a power supply from someone, connect it to your PC and check if it turns on. Not sure how to connect? Then it is worth contacting specialists.

3. The computer turned on, but Windows XP does not start

There are times when the PC is turned on, the monitor is working, but Windows XP does not load (black screen). The screen displays a window as in (Figure 1).

Figure 1 - DISK BOOT FAILURE - INSERT SYSTEM DISK AND PRESS ENTER

If you see such a message, it means that the computer cannot find the storage device on which the OS is stored. Simply put, the computer does not see the HDD, therefore Windows XP does not boot.

First of all, find out if the hard drive is connected correctly. If everything is fine with the hard drive, then the operating system has become unusable and you will have to reinstall Windows.

You can also see the text as in (Figure 2) when the computer starts up.

Figure 2 - Message

This means that system files are lost or damaged. In this case, you need:

1. Load the last successful configuration. To do this, you need to turn on the computer and press F8 on the keyboard. Then select the desired item from the displayed menu.
2. Follow the steps above, but click on "Safe Mode". Perform a system restore if the OS boots.

If the operating system does not boot at all, then it is most reasonable to reinstall Windows XP.

Of course, firstly, what needs to be done is to determine the malfunction, since the computer can break down in two cases:

1. Hardware failure, i.e. when a part fails.

2. Software malfunction, that is, if there is an error in the software.

Option 1. The computer does not respond.

If nothing happens when you press the Power button, no indicators are lit, the fans are not spinning - first of all, we check that the computer is connected correctly. We inspect the power cords, check if the switch on the back of the system unit is turned on.

If everything is in order, then the most likely reason is the failure of the power supply. At home and in the absence of experience with electrical appliances, it is extremely difficult to eliminate this malfunction. However, if you have the skills to build a PC, you can borrow a power supply unit from a friend and test your computer. In other cases, it is better to contact a computer service center.

Option 2. The computer responds, but does not boot.

If, when you press the Power button, the network indicator (green light) is on, the fans are spinning, but nothing appears on the monitor - most likely there is a hardware failure (if, of course, the monitor is connected correctly). What can you try to do?

Perhaps your computer is clogged with dust and there is simply no contact somewhere. In this case:

1. Open the computer cover and remove the RAM and video card.

2. Carefully remove dust from the system unit and removed slots.

3. Wipe well the contacts of the RAM and video card.

4. Put everything back in and check if the PC is working properly.

If the actions taken do not give a result, you will have to look for a faulty part. It's easier if you know BIOS version installed on your PC.

If you do not know the version of your BIOS, then just change the components one by one (borrowed from a friend). If this is not possible, the only way out is the same computer service center.

Option 3. The computer turns on, but Windows XP does not start.

If the computer turns on, an image appears, but WindowsXP does not load and a message like this appears:

DISK BOOT FAILURE - INSERT SYSTEM DISK AND PRESS ENTER.

This message indicates that no operating system storage device was found.

Check correctness connect hard disk, if everything is correct, the operating system is out of order.

This problem is solved quickly and painlessly - by reinstalling (in some cases, restoring) the operating system.

This option is also possible:

In this case, most likely, there is a problem with the system files, or their damage, or complete loss.

You can take the following measures:

1. “Loading the last known good configuration (with good parameters)”. To load the last successful Windows configuration after turning on the PC, press the F8 key. In the window that appears, select this download item.

2. "Safe Mode". To do this, when you boot the computer, press the F8 key (as in the previous paragraph), select "Safe Mode", if the system boots, go to the following path: Start -> All Programs -> Accessories -> System Tools -> System Restore. And following the wizard's prompts, try to restore an earlier working system.

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The problem of failing to boot Windows is quite common, even though Windows 7 and Windows 10 are very reliable operating systems and rarely crash. Of course, a huge role in this is played by the equipment, which is very diverse for home systems, and for budget solutions has a low fault tolerance factor.

In most cases, errors in loading the OS are to blame either on the users themselves, who, for example, performed an incorrect shutdown of the PC or accidentally deleted a system file, or on the hard drive on which a bad area was formed on the boot sector.

CHIP invites you to use our tips for solving the problem with booting Windows and restore the system to work.

Let's try to start

Faced with the impossibility of loading the Windows operating system, for a start it is worth restarting the computer a couple of times, because the problem can be one-time. If that does not help, then try to disconnect the computer for ten seconds by unplugging it from the mains. In this case, you need to de-energize the unit. uninterruptible power supply, if it is connected, and if we are talking about a laptop, then remove the battery.

It will also not hurt to temporarily disconnect external equipment: mouse, keyboard, printer, removable disks, wireless modules and more. If the reason lies precisely in external devices, connecting each of them in turn will help to find the culprit.

Of course, it is not always possible to solve the problem with the simplest manipulations, which means that you will have to start analyzing the text of the error message that appeared during computer startup.

Bootloader may be damaged

If you see a message on the screen with the text "BOOTMGR is missing", then the boot loader of the Windows 7 operating system is damaged or missing. To solve the problem, you will need a Windows 7 installation disc.

Reboot your PC and press function key to open the BIOS. Different PCs may have different keys, for example ESC, F2 or F6. Pressing the F8 key in Windows 10 will bring up a menu of special boot options, including Safe Mode. If that didn't work while rebooting the dozens hold down the Shift key.

So, if you managed to get into the BIOS, go to the "Boot device priority" section using the "+" or "PgUp" keys to set the CD / DVD drive as the first boot device. Then boot from the Windows installation disc and select the "System Restore" menu item. From the list of installed operating systems (if there are several of them), you need to select the one you need and click the "Next" button.

In the "System Recovery Options" window that appears, we are interested in two items: "System Startup Restore" and "Command Prompt". The first option will automatically eliminate the problem with starting the operating system, and if it fails, you will have to turn to the services of the second.

V command line type:

"Bootrec / rebuildbcd"

press "Enter" and agree to make changes to the boot configuration data by alternately pressing the "Y" and "Enter" keys. After that, it remains only to create a new boot sector using the command "Bootrec / FixBoot" and restart the computer.

No bootable disk found?

The appeared error message "No bootable device" and its numerous variations ("No Boot device found", "Invalid boot device", "Non system disk or disk error", etc.) indicates that the computer did not even start to start operating system, because it does not see the boot sector or even the hard drive.

To understand whether there is a problem at the software or hardware level, just go to the BIOS in the already familiar section "Boot device priority". If the hard drive (HDD) is not visible among the proposed options, then the problem is related to the hardware. Perhaps the data cable for the power supply or power supply of the hard drive has come off, or the drive has completely outlived its usefulness.

If the computer normally recognizes the hard drive, the reason is programmatic and lies in the Master Boot Record (MBR) - it is damaged or missing. Unlike those discussed above this situation is relevant both for Windows 7 and XP, but the solution is extremely simple.

Having booted from the installation disk, it is enough to execute just one command in the recovery console:

bootrec / fixmbr

Blue Screen of Death: Driver IRQL not less or equal

Critical messages Windows errors, which because of the background color are called "blue screens of death" (BSOD, Blue Screen of Death), are quite common problems not only in Windows 7 but also in Windows 10 (especially due to the installation of an incorrect update). Moreover, in the top ten, this screen can be green and red. A fatal error can be caused by malfunctioning hardware, for example RAM or lack of any system files.

Most often BSOD messages at an early stage of loading appear after updating device drivers and contain the text "DRIVER_IRQL_NOT_LESS_OR_EQUAL" along with the file name with the extension SYS. To remove the problematic driver in Device Manager, you can try starting Windows in safe mode, because it uses only a minimal set of drivers. To do this, press the F8 key while loading the OS and select the "Safe Mode" item.

If booting in safe mode blue screen death still appears, you need to return to the previous version of the driver, with which there were no problems. This can be done using a restore point, if such were created earlier.

In Windows 7, for this you need to press the F8 key during OS boot and select "Computer troubleshooting" in the menu that appears. Then we get to exactly the same menu "Recovery options", as when using the Windows installation disc.

This time we are interested in the "System Restore" item, in which you can select one of the available restore points.

Returning a copy of the system file

The absence of some important system files in the system, primarily drivers with the SYS extension, are often found in Windows 7 and 10. The most effective method solve the problem - return the loss to its place by finding a copy of it on installation disk Windows, borrowing from another computer with the same OS version or simply looking for it on the vast expanses of the Internet.

If you do not have a second computer at hand, then to search, download and copy files, you will need a LiveCD with an OS that does not require installation, for example, Kaspersky Rescue Disk 18.

One of the most convenient options is the Puppy Linux operating system, which will be up and running in less than a minute. This OS includes drivers for the most common models network cards, which means that it will not be difficult to access the Internet.

The exceptions are files system registry: System, Software, SAM, Security and Default, which are stored in the C: \ windows \ system32 \ config folder. Of course, you won't be able to replace them with copies from another computer, so the only option is to roll back to a restore point if it was made in due time.

Restoring boot Windows 10

And in order for the Windows 10 recovery tool, you need to open the menu of additional boot methods (by pressing F8 after turning on the computer) and go to the "Troubleshooting" section.

The chance to have time to press the desired key at this time (more precisely, the combination of F8 and Shift) is great if the system is installed on an MBR hard disk and the option is disabled quick launch... For fast system SSD drives you will have to try to press quickly or you will need bootable media.

In any case, you will need a Windows 10 installation disc. In our experience, a Windows 10 rescue disc will often fail to help restore your system. It is worth considering that the system image must be of the same bit depth as that installed on your PC. In addition, if you are using a bootable USB stick, it must be included with file system FAT32.

Alternatively, you can use the MS DaRT 10 (Microsoft Diagnostic and Recovery Toolset for Windows 10) download utility package. You can download it from the official Microsoft website. Windows images 10 are available for download from the Microsoft website.

Using Windows 10 bootable media

Connect the media to the computer, reboot, set in BIOS settings and first this disk and boot from it. After booting from it, select the system language. If Russian is selected, click "Next".

Next, you will be prompted to go to the installation or Windows recovery... Click System Restore. On the Select Action screen, click Troubleshoot.

Tens launch recovery options

In the recovery options section (screen " Extra options") There are 5 subsections:

• System Restore. When this option is selected, the standard rstrui.exe utility is launched, the purpose of which is to roll back the system to one of the saved checkpoints.
• System image recovery. Launches the Windows Deployment Wizard from backup created by the OS's own means.
• Startup recovery. Fixes errors in boot files and sections.
  Command line. Allows you to run various system utilities.
• Go back to the previous build. Rolls back to earlier installed version OS in case it has been updated to Windows 10.

Repair utilities

Almost all the problems with booting Windows discussed in this article can be caused by corrupted sector of hard disk (bad blocks). Even if, with the help of one of the manipulations discussed in the article, the operating system was brought back to life, it does not fit to check the working condition of the hard drive.

This can be done using the free MHDD application (downloadable), which can be run directly from the bootable CD. In the program menu, you must select from the list the channel to which the hard disk with the OS is connected, indicating its number. Then you can view the data of S.M.A.R.T, a kind of "medical record" of the hard drive (F8 key), or start scanning sectors for errors (F4 key), after allowing them to be corrected - "Remap | ON ".

If there are a lot of problem sectors, then the procedure can take hours or even a day. Considering that bad blocks tend to be concentrated at the beginning of the hard disk, it will be easier to move the OS partition away from the problem area - an indent of 2 GB will be enough.

For this purpose, boot disk with free editor partitions MiniTool Partition Wizard FE. In the program menu, you need to use the operation "Partition | Move / Resize ".

As we noted above, the BSOD can be caused by RAM, which, for example, is not capable of operating at higher frequencies. In such cases, the following text is possible on the blue screen: "PAGE_FAULT_IN_NONPAGED_AREA".

Testing RAM modules allows free app Memtest86. As with MHDD, Memtest86 can be operated from a bootable CD. The application does not require configuration and immediately after starting it starts diagnostics using a number of tests. The "Pass" menu item displays the number of completed test cycles, while "Errors" displays the number of errors recorded.