Please be aware that I own an Nvidia GeForce card and hence use Nvidia graphic drivers.
1. Uninstall the old Nvidia graphic driver.
2. Reboot to Safe Mode
3. Run Driver Sweeper (make sure to check "Nvidia - Display" ONLY). This freeware will delete all registry entries that have been left behind by your old Nvidia graphic driver.
5. Run RegCleaner.
6. Reboot again.
7. Make a restore point using Windows XP's System Restore tool or ERUNT. (Just in case you're installing a third party tweaked driver or a beta driver; restore points are handy in case something goes awry.)
8. Install the new Nvidia graphic driver.