I hope y'all are using Driver Sweeper when you upgrade drivers. Even Nvidia and ATI recommends using it. Uninstall the current drivers using Add and Remove Programs (or Programs and Features) reboot and go into Safe Mode. Run Driver Sweeper and have it get rid of all the bits that Windows left behind. Now reboot, don't let Windows install any default drivers and install your updated ones. Probably one more reboot in there.
I'm gonna try these out. Thanks for the heads up!