Windows XP

I have a customer that is getting an error like in MS article 314452 about a missing VirtualDeviceDriver. Believed to have come about by having 2 Virus systems running and then trying to clean out the old one.
Anyway, in trying to delete and re-add the entry VDD, I found there is NO "HKEY_LOCAL_MACHINE\System\CurrentControlSet" entry. I don't know how to replace that. This is a desktop PC a couple of years old with XP Home installed by OEM. I would like to do a repair of Windows, but all they have is a Restore CD, which I am afraid would take the PC back to original settings.
Any suggestions ?

 

I'm about to do the SFC /SCANNOW from a command prompt to see if it fixes some problems I have. Maybe that can be done with a restore disk too and might solve the problem?