Take a careful look at the BSOD (Blue Screen of Death).
Quite often, there is the name of the file being executed at the time of the failure – such as soandso.sys or sosandso.exe or sosandso.dll.
If you find one, then look for its predecessor in the backup folder (You DID back up your old files, right?), and try restoring it to its original spot.
Sorry that I don’t have a more definitive answer. I suspect that others will though.