I take a 'chill pill' before I reply to each one of your posts! Hehe...
This is one of those vague, generic Windows errors that pretty much states that there are some system files (and possibly a section of the registry) is jacked up.

Re-running XP installation from the CD (without any re-partitioning or formatting) should fix the problem as it would delete and rebuild the entire Windows directory as well as the registry. Though, that would mean most if not all of the applications and drivers will have to be installed again.

If you know all the stuff you had done prior to this issue and willing to troubleshoot, then it might be worth looking into it further..