Have you only tried the one restore point? Try making a restore point now/today...then go back through the restore points until one works?
The today restore point can then be used if you go back too far... I've only used the restore system a few times, and did what I'm suggesting now after one restore point failed; the reason why I'm not sure...but something didn't save properly.
p.s. I regularly backup using Norton Ghost. This software takes a complete image of my boot drive so incase of problems I can reimage my boot drive from dos
All of my personal files are on other drive/ partitions.