1. Upgrade to Windows XP SP3 if you haven't done so already. Restart your computer if necessary.
2. Log onto support.microsoft.com.

3. Hover your cursor over the 'Windows' option in the left pane of the site window.
4. Browse through the list of errors and click on the one that most closely describes your problem.
5. Click the green 'Run Now' button on the following page. Open the downloaded file and click 'Run.'
6. Click 'Detect Problems and apply fixes for me.' Microsoft Fix It will diagnose and automatically repair Windows XP for you.