How to Perform an In-Place Upgrade (Reinstallation) of Windows XP
This is a common method for repairing a pretty toasted system. It reinstalls the operating system but leaves all your software settings pretty much intact. It is a lot faster then re-installing the operating system and all your software. Make sure you read the link on how this can cause a loss of data and program settings!
Computer Stops Responding with a Black Screen When You Start Windows
This could mean you have a significant hardware problem. This will help you determine which direction to go.
Cannot Start Windows 2000 After You Install Windows 98 or Windows 98 Second Edition
You were not supposed to do things in that order, but hopefully there is an easy recovery from the situation.
Windows XP Does Not Start on a Computer That Is Configured for Dual Booting
Similar to the preceding article.
HOW TO: Use the Driver Roll Back Feature to Restore a Previous Version of a Device Driver in Windows XP
Have you installed a video driver or some other driver that drives your system bezerk?
How to Disable a Service or Device that Prevents Windows from Starting
A Description of the Safe Mode Boot Options in Windows XP
When to Reinstall Windows XP Service Pack 1
This is a common question. With NT service packs had to be reinstalled just about any time you did anything to the system. Is this the case with XP?
Description of the Windows System File Checker Tool
SFC is easy to forget you have as a tool, this article gives a good summary of when and how to use it.
How to Troubleshoot Hardware and Software Driver Problems in Windows XP
I think the title says it all
SYSTEM RESTORE: HOW TO: Restore the Operating System to a Previous State in Windows XP
Basic general info on how to use Sytem Restore
Damaged Registry Repair and Recovery in Windows XP
Have you applied SP1 yet?
How to Recover from a Corrupted Registry that Prevents Windows XP from Starting
Thanks DSmithLady for the link to this article! Other helpful links and tips as well as batch files bundled up in a ZIP are included in her post
HOW TO: Back Up, Edit, and Restore the Registry in Windows XP
Basic info, but if you are editing you registry for the first time, read this first!
Recovery console is to an NTFS XP system like a boot floppy is to WIN9X. Here are a few articles giving you some helpful info about the feature. RC is not something you want to discover at the time you really need it. It is best configured while everything is working. Then you can forget about it.
HOW TO: Install and Use the Recovery Console in Windows XP
Description of the Windows XP Recovery Console
HOW TO: Add More Power to Recovery Console By Using Group Policy in Windows XP Professional
Places to go for help with startup problems with Windows XP.
305595 - HOW TO Create a Boot Disk for an NTFS or FAT Partition in Windows XP
The first thing you need to have on hand, preferably before these problems begin, is a boot disk. You can go here to learn how to make one
308041 - Resources for Troubleshooting Startup Problems in Windows XP
Great guide covering numerous scenarios.
310560 - How to Troubleshoot By Using the Msconfig Utility in Windows XP
The Msconfig utility can also be used as a diagnostic tool by loading selected devices and services to help determine which one may be causing your problem.
315261 - The Computer Does Not Start After You Change the Active Partition by Using the Disk Management Tool
Even though Windows XP says this will work, sometimes it doesn't. Go here to find out what to do.
315403 - Stop 0x000000ED Error Message When Volume on IDE Drive with Caching Enabled Is Mounted
Another name for this one is Unmountable_Boot_Volume. Check out this article for possible solutions..
320252 - Error Message Windows Could Not Start Because the Following File Is Missing or Corrupt...If you are getting this message,this link will help you with the repair.
324103 - HOW TO Troubleshoot Stop 0x0000007B Errors in Windows XP
This problem is also know as a Inaccessible_Boot_Device error. This article describes possible causes and ways to fix this problem.
329450 - Cannot Start Windows XP After Installing Service Pack 1 and Then Performing a System Recovery Operation
Here are instructions on what to do if performing a system recovery to uninstall SP1 does not work.
This is a performance trace visualization tool for use with Windows XP systems.
This version of BootVis.exe is compatible with final release of Windows XP (build 2600) and resolves a compatibility issue when using third-party IDE drivers.
Articles to help with diagnosing shutdown problems.
266169 - How to Troubleshoot Problems with Standby Mode, Hibernate Mode, and Shutting Down Your Computer in Windows XP and 2000
This covers a variety of possible shutdown issues.
283096 - Improper Shutdown May Affect System Restore
Double check your system restore points to make sure that improper shutdowns have not caused you to lose them.
305788 - HOW TO Increase Shutdown Time So That Processes Can Quit Properly in Windows XP
Is your computer trying to shutdown too fast causing improper shutdowns? Read this article to find out how to eliminate this possibility.
The following are mostly self-explanatory by titles.
307274 - Windows XP Stops Responding (Hangs) During Windows Shutdown
311806 - Windows XP Restarts When You Try to Shut Down Your Computer
314101 - Computer Hangs During Shutdown or Displays a Cannot Find Enough Free Resources Error Message
315327 - Error Message When You Shut Down Computer DEVLDR Not Responding
Getting this error message? This article explains how to get rid of it.
315664 - Computer Does Not Shut Down Properly if Selective Suspend Is Enabled
Check this article to see if selective suspend may be your problem.
General Repair Section
Troubleshoot Windows XP Professional Great comprehensive troubleshooting guide.
101790 - Information on how Last Known Good Control Set works
242062 - General USB Troubleshooting in Windows XP and 2000
247575 - Chkdsk Does Not Use Backup Boot Sector to Fix Corrupted FAT32 Boot Sector
315688 - How to Locate and Correct Disk Space Problems on NTFS Volumes in Windows XP
What to do if 301224 - System Restore Restore Points Are Missing or Deleted
Check back from time to time for updates.
DSmithlady also contributed a lot of work to this FAQ as well.