Microsoft Knowledge Base Article 316434 contains the following INTRODUCTION:
Many issues that you may experience on a Windows XP-based computer occur because of an incompatible or corrupted program.
To determine whether this is the case, you can either perform a clean boot or restart Windows without starting the program
This article describes how to perform advanced clean-boot troubleshooting to determine whether the problem in question is affiliated with the core operating system or with a program that is loading in the Windows environment.
For additional information about how to clean boot your computer, click the following article number to view the article in the Microsoft Knowledge Base:
310353 How to perform a clean boot in Windows XP