How to Undo the Last System Restore in Vista and Windows 7
This will show you how to undo the last System Restore that you did. This can be helpful if the previous System Restore had unexpected consequences that you did not want, or it did not help.
You would have had to of previously done a System Restore in order to be able to undo it. (I know, duh.)
If you do a System Restore when the computer is in safe mode or Windows Recovery Environment (WinRE), then you will not be able to undo the restore operation. However, you are able to still run System Restore again and choose a different restore point if available.
System Restore uses this service: Volume Shadow Copy