Well, you are welcome to keep talking around the point, or you can disable the auto restart and report the actual errors on the Blue Screen, which may include the driver causing the fault.
Yes, the error can be casued by a driver, and it may be the new Nvidia Driver trying to write to sections of memory or trying to do things it's not supposed to do. Go to Nvidia's site and see what's there for old drivers and use those.
By the way, I have no idea how good the tech was, but you can generally find out what was installed in a system previously by parsing through the driversfiles folder in XP.
C:\WINDOWS\system32\ReinstallBackups\
Just search for *.PNF, those are INF installation files which have been installed so become Precompiled for installation and subsequent usage like reinstalls. If you hunt through there, you can find out what was previously installed. You can open these files in Notepad, but open the related INF, not the PNF which is not really legible.
Anyway, I'm not going to be able to help you from such a distance. It's something that is easiest to resolve looking at the actual machine. Even then, it could take hours.