You will need to try Method Two here: System Restore - How to
If you don't have a Windows DVD, you will need to make one using these instructions: Create a Recovery Disc
This was quite a problem with Vista SP1. Unfortunately, there is no specific fix.
If System Restore doesn't work, we could try to revert the image, but that would leave the system in a very messy state.
We need to try System Restore.
However, Microsoft have taken measures. SP2 was a lot better, and functions of the new dism.exe on Windows 7 allow for easier image reverting.
The very best of luck with System Restore.
P.S. If System Restore is a success, do NOT try SP1 again, until I can assess your system! Thanks!