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Can't Start Windows XP

Before troubleshooting Windows XP startup, it is important to understand that XP startup is a process, not an event. If you can't start XP, it means that an event took place that prevented XP from completing its startup process. The distinction is important in this type of troubleshooting because the point where the event took place within the process is what should lead you to finding a solution. An additional distinction about hibernation or standby is also required; failure to bring a system out of hibernation or standby is not a startup problem. Go here for information on hibernation and standby problems.

Narrow Down the Problem

Depending on what you have done so far in your attempts to fix the problem, and depending on where the problem is and what it is, using the Last Known Good Configuration feature may or may not allow you to start XP. Try the the Last Known Good Configuration feature now before you try anything else.
 
Scan the Knowledgebase articles listed below first. Check to see if your specific issue is addressed there.
If you have Service Pack 2 or later installed, and if your machine is continually rebooting, there is a startup option that you can use to prevent XP from rebooting on a system error.

Start the machine as you would start it to get into safe mode by pressing F8 after the BIOS screen has displayed. Select the option named Disable automatic restart on system failure. This will allow you to obtain any STOP error code that might be causing the problem. Once you have the stop code, you can look it up on the Stop Errors page here. You can also refine your troubleshooting plan by using the site search facility at the top of the page.
If the machine is hanging or rebooting after you type your password, and if you can access any other user account in normal startup mode then you may have a corrupt user account, or the account may be trying to start a corrupt application that the other user accounts don't try to start.

If the problem occurs on other user accounts then the cause could either be a corrupt system registry or all the accounts may be trying to start the same corrupt application. Try starting the machine in safe mode.
 
If the machine is hanging or rebooting after you type your password, and if you do not have access to any other user account then try to start the machine in safe mode and create a new user account. If you can create a new user account, go back to the previous step and try logging on to the new account.

If the new account works then recovering from a corrupt user account is fairly straightforward:. Read this Knowledgebase article. If you have trouble accessing the user data in the corrupt user account, read this Knowledgebase article.

Safe Mode

If you have not yet tried to start in safe mode, do it now. If you need help with safe mode, read this Knowledgebase article.

If you cannot access any user account in safe mode then go to Corrupt System Registry.

If you can access any account in safe mode then you can choose to:
  • Treat the problem as if it has been confirmed that you have a corrupt user account.
  • Narrow the problem down further by disabling all non-essential startup services and applications then selectively re-enabling them one at a time and rebooting, and then attempt to logon normally after each reboot. You will need to use msconfig to do this. Read about using msconfig to troubleshoot. You will also need this knowledgebase article on troubleshooting the startup process.
If you choose to treat the problem as though it is a confirmed corruption of the user account then read this knowledgebase article. If you have trouble accessing the user data in the (assumed) corrupt user account, read this knowledgebase article.
It may seem odd to some that in troubleshooting your problem you would be asked to pretend that you are dealing with a completely different problem, which is, in effect, what you are doing if you choose to treat the problem as a corrupt user account without narrowing the problem down further. However it is a valid and logical thing to do in this kind of troubleshooting.

There is a risk that neither treating the problem as a corrupt user account nor spending endless hours trying to narrow it down to something specific will result in a fix for your problem, which means you will be left with only one possible way to go; treat the problem as if it is a corrupt system registry.

The question is, how much time and effort are you prepared to invest while there is a risk you won't find the root cause? To put that another way, what is more important, knowing what the real cause is or getting out out of the mess you're in as quickly as possible?

At least in this kind of troubleshooting, by assuming that the problem is X without knowing for sure that the problem is X, you can save an awful lot of time and effort because the problem is in the general direction of X. This holds true because the only real way to confirm that you have a corrupt user account is to perform a clean boot and do exhaustive advanced clean-boot troubleshooting; if the problem persists, see a doctor.
If, at any stage of the troubleshooting process so far, you have been able to gain access to your data then perhaps you should back it up before you do anything else.

Corrupt Registry

If all else fails, you will have to try to treat the problem as if it is a corrupt registry issue. You can attempt either or both of the methods listed below; you simply need to decide what to try first. You don't have to be suffering a black screen and constant reboots to use the information at the first article because it's the information in the article that counts.

Black startup screen is briefly displayed and your computer restarts repeatedly when you try to start Windows XP

The article describes several recovery methods. Don't forget to ignore the symptoms if you are treating the issue as if it is a corrupt system registry.
How to recover from a corrupted registry that prevents Windows XP from starting

Again, if you are treating your issue as if it is a corrupt system registry, ignore the symptoms.

Disk Corruption

If you have followed the troubleshooting steps above and have tried all the methods described but still cannot access your system then your last hope is to treat the problem as if it is a serious disk corruption problem.

Knowledgebase Articles

Hardware Malfunction Results in System Error Message

During the Windows startup process, the computer may stop responding (hang), and you may receive the following error message:

*** Hardware Malfunction
Call your hardware vendor for support
*** The system has halted ***


One of the following error messages may also be included:

NMI: Parity Check / Memory Parity Error

NMI: Channel Check / IOCHK

NMI: Fail-safe timer

NMI: Bus Timeout

NMI: Software NMI generated

NMI: Eisa IOCHKERR board x

Error Messages When You Start Your Computer if Windows Program Files Are Missing or Damaged

When you start your computer, you may receive an error message that is similar to the either of the following:

Windows could not start because of an error in the software
Load needed DLL's for Kernel
Computer stops responding with a black screen when you start Windows XP

When you try to start Windows XP, the computer may appear to stop responding (hang) with an empty, black screen immediately after the power-on self test (POST) is complete and before the Windows XP logo typically appears on the screen.
Windows XP Resource Kit: Troubleshooting the Startup Process

If you are not technically inclined then give this article a miss. It is an excellent resource for those seeking to understand more about the startup process.
How to Disable a Service or Device that Prevents Windows from Starting

If a service or device driver is started automatically and is incompatible with the current version of Windows, the service or device driver may not allow Windows to remain running long enough for you to shut down the service or disable the outdated device driver.
How to recover from a corrupted registry that prevents Windows XP from starting

This article describes how to recover a Windows XP system that does not start because of corruption in the registry. This procedure does not guarantee full recovery of the system to a previous state; however, you should be able to recover data when you use this procedure.
Black startup screen is briefly displayed and your computer restarts repeatedly when you try to start Windows XP

Describes that a black startup screen may briefly display and your computer may restart repeatedly when you try to start Windows XP. This article contains a workaround for this problem.
Windows XP logon screen does not appear and the computer continuously restarts

When you start your computer, the Microsoft Windows XP startup screen appears, and then the computer may restart. The Windows XP logon screen does not appear.
Windows XP Welcome Screen Appears to Stop Responding (Hang) During Logon

When you use the Welcome screen to log on to a computer that is installed as a home computer (a computer where a network domain has not been specified), the computer appears to stop responding (hang) and you receive the following message under the user name: loading your personal settings...
Hardware Malfunction Results in System Error Message

During the Windows startup process, the computer may stop responding (hang), and you may receive the following error message:

*** Hardware Malfunction
Call your hardware vendor for support
*** The system has halted ***


One of the following error messages may also be included:

NMI: Parity Check / Memory Parity Error
NMI: Channel Check / IOCHK
NMI: Fail-safe timer
NMI: Bus Timeout
NMI: Software
NMI generated
NMI: Eisa IOCHKERR board x

Your Windows XP computer stops responding after you log on

Provides a resolution for an issue that occurs when you log on to a computer that is running Windows XP, an "Applying local settings" message appears, and the computer stops responding.
How to troubleshoot registry corruption issues

This article describes how to troubleshoot registry corruption issues. Describes how to create a startup disk to start your operating system if the startup record becomes corrupted. The startup disk contains only the files that you must have to start the operating system.

If your computer does not restart, the registry hives may be corrupted. The error messages may vary. They can include any of the following:

Windows could not start because the following file is missing or corrupt:\WINNT\SYSTEM32\CONFIG\SYSTEM.ced

Windows could not start because the following file is missing or corrupt:\WINNT\SYSTEM32\CONFIG\SYSTEM

Windows could not start because the following file is missing or corrupt:\WINNT\SYSTEM32\CONFIG\SOFTWARE

System hive error

Stop 0xc0000218 (0xe11a30e8, 0x00000000, 0x000000000, 0x00000000) UNKNOWN_HARD_ERROR

Stop: 0xc0000218 {Registry File Failure} The registry cannot load the hive (file): \SystemRoot\System32\Config\CorruptHive or its log or alternate. It is corrupt, absent, or not writable.

The splash screen that appears at startup does not display the complete Windows XP version information

After you install Windows XP Service Pack 2, the Windows XP splash screen that appears at Startup does not display the complete version information about your operating system.
Your Computer May Pause with a Black Screen If You Press ESC During Startup

If you press the ESC key while your computer is starting, your computer may pause with a black screen. If this problem occurs, you can press any other key to resume the startup process.
Resources for troubleshooting startup problems in Windows XP

Describes how to troubleshoot startup problems in Windows XP if you receive an error message during startup, or your computer stops responding during startup, or, after an upgrade, programs that previously loaded during startup no longer start.
How to Modify the List of Programs that Run When You Start Windows XP

This article explains how to use the Group Policy snap-in to create or modify the list of programs that start automatically when you log on to your Microsoft Windows XP-based computer.
How to edit the Boot.ini file in Windows XP

This article describes how to view and manually configure the Boot.ini file in Windows XP from within the Startup and Recovery dialog. In Windows XP, you can quickly and easily locate the Boot.ini to verify and/or edit the file.
"Dri_kbfiltr Not Found" Error Message on Startup

After you start Windows XP Professional, you may receive the following error message: dri_kbfiltr could not be found This issue may occur after you upgrade from Windows XP Home Edition to Windows XP Professional.
The computer is stuck in a restart loop after you upgrade from Windows 98 or Windows Me to Windows XP

After you complete the process of upgrading from Microsoft Windows 98 or Microsoft Windows Millennium Edition (Me) to Microsoft Windows XP, and then you restart your computer, your computer may reach the Windows XP startup screen, shut down, and begin the restart process again. The startup process never completes, and your computer remains stuck in a restart loop.
"Unhandled Exception c0000005" Error Message During Windows Startup

When you start Microsoft Windows XP Home Edition, you may receive the following error message:

Unhandled Exception c0000005 at address: 100016b8 PromulGate Universal has encountered a problem and needs to close.
Black screen on startup after you upgrade to Windows XP Professional

After you upgrade your Microsoft Windows XP Home Edition-based computer to Microsoft Windows XP Professional, you may experience one or more of the following behaviours: When you start the computer, the display turns black with a large white pointer; You cannot increase the screen resolution to higher than 640 × 480 pixels; You receive the following error message when Windows starts:

\\.\DRI_KBFiltr The System cannot find the file specified.
The computer stops responding during startup

When you try to start your Microsoft Windows XP Service Pack 1 (SP1)-based computer, it may stop responding or "hang".
Blue-Screen Error Message Appears During Startup on Computer That Has Sidewinder Gamepad

When you use a Microsoft SideWinder Game Pad Pro device on a computer that runs Windows XP, you may receive the following error message on a blue screen:

Fatal System Error:
0x000000a0 (0x00000002,0x00070124,0x00000000,0x00000000)

Error Message: Windows could not start because the following file is missing or corrupt

Explains how to resolve the issue if a "Windows could not start because the following file is missing or corrupt" error message appears. You can either run Windows XP Setup again, cancel Windows XP Setup, or install Windows XP on a clean hard disk.
Error Messages When You Start Your Computer if Windows Program Files Are Missing or Damaged

When you start your computer, you may receive an error message that is similar to the either of the following: Windows could not start because of an error in the software Load needed DLL's for Kernel.
You receive a "Windows could not start because the following file is missing or corrupt: Isapnp.sys" error message at startup

When you try to start Microsoft Windows XP or Microsoft Windows 2000 , you may receive one of the following error messages, depending on your operating system.

Windows XP
Windows could not start because the following file is missing or corrupt: \windows\System32\Drivers\Isapnp.sys

Windows 2000
Windows could not start because the following file is missing or corrupt: \Winnt\System32\Drivers\Isapnp.sys
"Windows could not start because the following file is missing: \system32\drivers\ntfs.sys" error message in Windows XP Service Pack 2

If you install the 826939 Update Rollup 1 for Windows XP on a Windows XP SP2-based computer, the computer may not always start. You may receive a message that says that the \System32\Drivers\Ntfs.sys file is missing.
A computer that uses an Intel EM64T processor may stop responding during startup

Fixes a problem that may occur on a computer that is running an x64-based version of Windows if the computer uses multiple processors or uses more than 8 GB of RAM. Provides a hotfix to resolve the problem.
"Operating System Not Found" or "Missing operating system" error message when you start your Windows XP-based computer

Describes issues that can cause your Windows XP-based computer not to start and how to resolve these issues.
How to start your computer by using the Last Known Good Configuration feature in Windows XP

Describes how to use the Last Known Good Configuration feature when you have problems after you make a change to your computer. This feature restores registry information and driver settings to those that were used at the last successful startup.
"Windows Cannot Find Openme.exe" Error Message When You Start Windows

When you start Windows, you may receive an error message similar to the following: Windows cannot find openme.exe.
Problems when Windows XP tries to load the Agp440.sys service

When you install Windows XP, you may experience one or more of the following symptoms: When you restart your computer, you may be prompted to use the Last Known Good configuration. When you do so, your computer may stop responding (hang) during the restart, and each time you restart thereafter; You may be prompted to run ScanDisk. When you do so, your computer may stop responding (hang). If you do not run ScanDisk, your computer may start correctly. However you are prompted to run ScanDisk every time you start your computer, and if you do so, your computer may stop responding (hang); When you restart your computer, your computer may stop responding (hang); If you try to restart your computer in Safe mode, your computer may stop responding (hang) when Windows XP tries to load the Agp440.sys service.
You receive a "Generic Host Process" error message after you start the computer, or DBCS attachment file names are not displayed in Rich Text e-mail messages

If you installed security update 873333 (MS05-012), you may experience one or more of the following problems:
  • You may receive the following error message after you start the computer:
    • Generic Host Process for Win32 Services Error
  • Note: This problem only occurs in Microsoft Windows XP Service Pack 2 (SP2).
  • File names are not displayed in e-mail messages that include file attachments when the following conditions are true:
    • The file name contains double-byte character set (DBCS) characters.
    • The file name is longer than 42 characters.
    • Note: This problem only occurs when the e-mail message format is Rich Text.
  • An application that implements the IMallocSpy debugging interface may experience heap corruption after you install security update 873333.