1. If you have a working floppy drive, you can download the Windows XP Setup boot disks (six volume floppy set):
http://support.microsoft.com/kb/310994/en-usBe sure to get the right set; Windows XP (Home or Professional), Original, Service Pack 1 (SP1), or SP2.
2. Have you tried the options available on the 'Windows Advanced Options Menu"? At start-up, tap the F8 key about once per second until the Windows Advanced Options Menu appears. I would try in the following order:
o Last Known Good Configuration
o Safe Mode
o Safe Mode with Command Prompt
3. How to start the System Restore tool at a command prompt in Windows XP (Safe Mode with Command Prompt). A system restore to an earlier time will also load version of registry for that time:
http://www.easywindows.com/easydos/edmessages/977.html http://support.microsoft.com/kb/304449/