system restore undo failed

Help!
I restored my system to a date about a month previous and
it didn't help. Now I'm trying to undo the restore and
it keeps failing (Just returns the error message UNDO
FAILED) and doesn't give me a clue what to do. Am I
stuck in the past? This wouldn't be so bad, but now I
don't seem to be able to install any windows
updates/patches. when I try to update with patches, it
says installation failed and doesn't let me install
anything. Help!
Kman