I decided to do a system restore and even that was made useless!
I've never had much success with SR. I now use Easeus Todo Backup, and take regular "Images" of the O/S partition. If this becomes so screwed up that you can't boot, or access the program, it will also run directly off a CD which you can make when first installing the programme.
Note - from the above, you will (hopefully) be aware that I have the O/S and "My documents" on separate partitions - in fact, on this machine they are on different drives. I also do regular backups of those files, but it's inevitably a much larger size, and keeping the two apart means an O/S restore only takes minutes.