Driver Cleaner.NET is a program which helps you to remove parts of drivers that are left after uninstalling the old drivers. The program is for ATI, nVidia, Creative, Realtek, SIS, 3Dfx, S3 and more drivers. First you need to uninstall the drivers from the control panel, then reboot to safemode. After rebooting, run the program. For a good description of what steps you should take, you really need to read the help file as it contains detailed instructions and descriptions.