Hi, Compmom, and welcome to Bleeping Computer.
It sounds as though you might have some other infections. I think that the first thing to do is to submit a HijackThis! log in the Hijack forums of Bleeping Computer. First read the pinned post about "How to Submit a Hijack Log" here
and then submit a log. It's always possible that the regedit file just became corrupted, but it's a good idea to see if the problem is malware related before trying to fix it some other way. Good luck!