There's no such thing as "a system restore from an xp disk" ?
You can either:
1. do a System Restore using the Help and Support Centre to a saved restore point
[http://support.microsoft.com/kb/306084]
or
2. Do a repair/install using your XP disk [http://michaelstevenstech.com/XPrepairinstall.htm]
I think 1. has the greater chance of success, but this sure is an abstruse problem
:-(