When we were in the Tavern talking one topic was backing up the registry in Windows systems. A problem with the inbuilt Windows restore program is that it doesn't backup and restore all the security hives (SAM). These can contain program licensing information and days to program expiry, so for obvious reasons developers and Microsoft don't want you to be able to modify these areas. However if they become corrupted you can be in real trouble.
For some years I've used a program ERUNT - The Emergency Recovery Utility NT Registry Backup and Restore for Windows NT/2000/2003/XP. This backs up and allows you to restore the
complete registry to a previous date. The latest FAQ says the program will work with VISTA.
Before installing any new program I always make an ERUNT backup so that if the program leaves registry entries behind after an uninstall or fails to uninstall the system can always be restored to a pre-install state.
ERUNT and NTREGOPT
Using ERUNT for backing up the registry 
Bob.