Problems that you're troubleshooting in Windows XP often originate in the boot process. As such, one of your key troubleshooting techniques should be to create a boot log. Creating such a log is a relatively easy process.
Follow these steps:
After the system restarts, launch Notepad, and open the C:\Windows\Ntbtlog.txt file. This file contains a list of all of the files that Windows XP attempted to load during startup.
Every line in the file will begin with either "Loaded driver" or "Did not load driver," which makes it easy to determine what drivers or services could be causing the problem. In either case, the path and filename of the driver or service will follow.