This topic was prompted by a problem that one of our clients was facing. He ran into a problem trying to get his computer to shut down:

He was running Windows XP Professional and it absolutely refused to shut down. Every time he tried to shut down it could go through the motions, but when it got to the point to turn off the machine, the BIOS screen could come up and the machine reboots.

Annoying; well let’s look at the causes before we tell you what worked for our Client. There are three basic sources of automatic reboot problems:

· Recovery settings

· Software incompatibilities, including driver issues

· BIOS problems

Recovery Settings

One of the things that is quite different about Windows XP compared to Windows 9x (9x is shorthand for Windows 95, Windows 98, and Windows Me in all their various versions), is that one can control how it responds to certain critical errors—those that cause the infamous Blue Screen of Death (BSOD). In Windows XP, the default setting is for the computer to reboot automatically when a fatal error occurs. If that fatal error only occurs when you’re shutting down, the system reboots automatically.

If you haven’t changed any of the system failure settings, you should be able to see the error by looking in the Event Log. But a better long-term solution is to turn off the automatic reboot so you can actually see the error when it happens—chances are it will tell you enough about itself to let you troubleshoot further. To change the recovery settings to disable automatic rebooting:

· Right-click My Computer and then click Properties.

· Click the Advanced tab.

· Under Startup and Recovery, click Settings to open the Startup and Recovery dialog box.

· Clear the Automatically restart check box, and click OK the necessary number of times.

· Restart your computer for the settings to take effect

Now when you go to shut down and a fatal error occurs, you’ll at least see it and it won’t cause an automatic reboot. You still have to sort out what’s causing the problem, and that gets us to the next cause.

Software Incompatibility

Most of the time a fatal error or BSOD is a software or driver problem, and troubleshooting these can be tricky. The mechanism for troubleshooting, however, is pretty much the same for any problem on a PC. The first thing to look at is what’s changed—what new software program or drivers have you added, usually just before the problem started. This sounds easy and it often is, but if it’s something you’ve lived with for a while, you’ll often have no idea what the proximate cause is. When you do, it’s a lot easier. When you don’t, you need to do a bit of research to find out if there is a specific cause for the particular error message you’re getting (when you have one) or a known issue with certain programs or drivers that causes the behavior you’re seeing.

Often someone else has had a similar problem and will offer a solution. And it’s always a good idea to check for updates to any of your critical hardware drivers on the manufacturer’s Web site, although windows update helps keep you up to date.

BIOS Problems

Finally, the last and often trickiest to troubleshoot source of reboot problems: your computer’s BIOS. If there is a problem in your BIOS, or sometimes even in the firmware for one of the other pieces of hardware installed in your machine, it could cause an instability and lead to one of those automatic restarts that we talked about in the first section. Especially if the problem is in the Advanced Configuration and Power Interface (ACPI) portion. The good news is that these problems are much less common than they used to be in the bad old days. But it never hurts to check with your computer manufacturer to see if there’s an updated BIOS available.

This step-by-step article describes how to troubleshoot “Stop 0×0000007B” error…

This step-by-step article describes how to troubleshoot “Stop 0×0000007B” error messages in Windows XP. This article describes issues that can cause this Stop error including boot sector viruses and device driver issues or hardware issues. If you cannot resolve the problem after you review these issues, use the general troubleshooting steps that appear at the end of the article.

This article is intended for advanced computer users. If you are not comfortable with advanced troubleshooting, you might want to ask someone for help or contact support.

When you start your computer, you may receive one of the following error message.

When you start your computer, you may receive one of the following error messages:

• STOP: 0×0000007B (parameter1, parameter2, parameter3, parameter4)
  INACCESSIBLE_BOOT_DEVICE
• Setup has encountered a fatal error that prevents it from continuing.Contact your product support representative for assistance. The following status will assist them in diagnosing the problem.

  (0×4, 0×1, 0, 0)

  Setup cannot continue. Power down or reboot your computer now.

You may also receive a “Stop 0×0000007B” error message during Windows XP Setup when the Setup program restarts during the installation process. When you receive a Stop error while the Setup program is running, you receive the second error message. To troubleshoot this issue, read the following four sections to determine if any one of the issues applies to you. If none of the issues apply to you, use the following general troubleshooting steps at the end of the article.

Boot-Sector Viruses

You may receive a “Stop 0×0000007B” error message if your computer is infected with a boot-sector virus. If the problem is intermittent and you can start Windows, check your computer for viruses. If you find a virus, also check any floppy disks for viruses before you use them again.

Note You may have to use more than one brand of virus-detection software to detect and remove various viruses.

Important If your computer has been infected, it may be open to additional forms of attack. We recommend that you rebuild infected Internet-facing servers.
If a virus has infected your Windows XP-based computer and a virus-detection program cannot remove the virus and repair the system, you must repartition and format your hard disk and reinstall Windows XP. For additional information about partitioning and formatting a hard disk with Windows XP

Device Driver Issues

You may receive a “Stop 0×0000007B” error message in the following scenarios:

• A device driver that the computer boot controller needs is not configured to start during the startup process.
• A device driver that the computer boot controller needs is corrupted.
• Information in the Windows XP registry (information related to how the device drivers load during startup) is corrupted.

Windows XP requires a miniport driver to communicate with the hard disk controller that is used to start your computer. If Windows XP does not supply a device driver for your controller or if Windows XP is using a corrupted or incompatible driver, you must replace the driver with a valid copy that is compatible with your controller and Windows XP.

During the first phase of the Windows XP installation, Setup displays the following message at the bottom of the screen:

Press F6 if you have to install a third-party SCSI or RAID driver.

Press F6 and then follow the instructions to install a mass-storage device driver from your Original Equipment Manufacturer (OEM).

To determine if your hard disk controller is compatible with Windows XP and to obtain information about drivers that are included on the Windows XP CD-ROM or that are available for download, see the latest Windows XP Hardware Compatibility List (HCL).

If your hard disk controller is not listed on the HCL, contact the manufacturer of your computer, system board, or hard disk controller for information about the availability of a driver. Microsoft does not guarantee that a resolution is available for non-HCL equipment.

If the System hive in the Windows XP registry is corrupted, Windows XP may not be able to load the miniport device driver that the boot controller requires. To resolve this issue, restore a registry backup.

Hardware Issues

You may receive a “Stop 0×0000007B” error message if there is a resource conflict between the boot controller and another controller or between SCSI devices. You may also receive this Stop error message if drive translation is not being performed or if drive translation was changed. To troubleshoot this issue:

1. If an IRQ or I/O port address conflict exists between the boot controller and another controller, Windows XP either stops responding (hangs) or displays a “Stop 0×0000007B” error message. If you recently added new hardware, remove the new hardware or reconfigure it so that it does not conflict with the resources of any other installed controllers.
2. If you are using a SCSI hard disk, check the SCSI chain for correct termination. Remove any unused SCSI devices or make sure that each SCSI ID is unique.

Make sure that drive translation is turned on (if it is required) and that it has not been changed. For example, if you recently switched controllers, this issue may occur.

Other Issues

Other potential causes of a “Stop 0×0000007B” error message include:

• The boot volume is corrupted and cannot be initiated by Windows XP. If the file system is corrupted and if Windows XP cannot initiate the boot volume during the startup process, either move the drive to another computer that is running Windows XP and run the chkdsk command on that drive or try to create a parallel installation of Windows XP on the drive (in a separate folder). The Windows XP Setup program checks the integrity of the volume before it copies files, and it may fix some problems in the process.
• You are installing Windows XP on a mirrored boot partition that was created by Microsoft Windows NT 4.0. Windows XP does not support Windows NT 4.0 Ftdisk volume sets. If you are running Microsoft Windows 2000, you must convert all Ftdisk volume sets to dynamic volumes before you upgrade to Windows XP. If you are running Windows NT 4.0, break any mirrors and back up all the data on the stripe, the RAID5, or the extended volume sets before you upgrade to Windows XP. Ftdisk sets might not be accessible after the upgrade.

General Troubleshooting

If none of the issues that have been described in this article apply to you, use the following general troubleshooting steps:

1. If you receive one of these error messages while you are installing Windows XP, update the computer BIOS or obtain Windows XP drivers for your hard disk controller (from the manufacturer of your computer, system board, or hard disk controller), or do both. For information about how to update your computer’s BIOS or obtain Windows XP drivers, contact your computer manufacturer.

Use the Last Known Good Configuration feature. This may resolve the problem if you recently installed an incompatible device driver for your boot controller.

Use the Repair option with Windows XP Setup

Restore a registry backup.

Today a client friend of mine walked in to my office that his computer kept restarting after he had returned from his trip..after resetting his machine to stop auto restarting..loo…the beknown blue screen of death showed up with this error..showing STOP: c000021a {Fatal System     Error} The Windows Logon Process system process terminated unexpectedly     with a status of 0xc0000139 (0×00000000 0×0000000) The system has been     shutdown.\This is error occurs when either Winlogon.exe or     Csrss.exe fails. Usually due to: Mismatched system files have been installed. A Service Pack installation has failed. A backup program that is used to restore a hard disk did     not correctly restore files that may have been in use. An incompatible third-party program has been installed.

Solution. The solution microsoft gives for this is really too technical, thats why my client brought it to me…however, try to boot from the last known best configuration or if you have a bootable xp CD, perform a repair of the operating system at the second setup screen.. That fixed my problem..

http://support.microsoft.com/default.aspx?scid=kb;en-us;156669