Since someone was talking about restore points, maybe it's time to remind people of the free ERUNT utility -
http://www.larshederer.homepage.t-online.de/erunt/
This allows you to set what is effectively a "restore point" very quickly, anytime you like (read the blurb). This is accessible through the Windows Recovery Console, so that Windows and the GUI does NOT need to be up for you to fully restore the Registry to a previous point.
I have the Autobackup option set, so that everytime the PC starts successfully a restore point is automatically generated (you can set the number of points saved and they are automatically deleted on an "oldest first" basis, so that things don't get too full).
