If you’re running Windows 2000 or Windows XP, one additional quick-fix feature that you should be aware of is Last Known Good. Every time that Windows 2000 or XP completes the boot process, it makes a copy of the current Registry and stores it. So, if you make a change (like installing an incorrect driver) and want to attempt to reverse it with minimal effort, try rebooting the system using this option. To get to Last Known Good, press F8 at the operating system selection screen, and then choose this option from the menu.
If all goes well, you should boot into your system using the previous configuration settings, with no harm done. However, you should note that the backup is overwritten every time the boot process completes. So, if you were to install a bad driver, reboot completely, then notice the problem and attempt to reboot and use Last Known Good, you would unfortunately be out of luck. In this particular situation, your best bet might be to use the Driver Rollback feature if you’re running Windows XP, and then try a System Restore.