check your event logs to make sure it is actually the gfx driver thats causing the issue.
(ctrl panel, admin tools, events, apps or critical)
if it is the driver then a repair install is your best solution as this will replace the HAL (hardware abstraction layer). reason for this is when windows initially boots it loads either an nvidia compatible or amd compatible base driver. if it loads the wrong 1 you will get system instability.
theres 2 ways of doing it , either run the windows upgrade option from the boot dvd or use the repair install from the windows boot.
repair will install a fresh version of windows and is safest. but the upgrade option should allow you to repair windows in place without crating a new windows install or have any of the issue associated with the repair install but can leave some bad reg entries and client protocols
you can of course take the pro route and manually change the HAL but this isnt for the beginner.
either way look here for more info and specific instructions on what to do.
http://support.microsoft.com/kb/249694#method9