If a Reboot Doesn't Fix It, a Reformat Will! The TechZone has the step-by-step.

For anyone that has reinstalled their operating system a few times the process seems pretty straightforward as they have found all of the gotchas the first few times. I have lost mail and contacts but not much else over the years by following (or not following) a system to reload my operating system and software. This purpose of this guide is to give you a checklist to follow so that a reloading of Windows goes smoothly the first time.

How To Reinstall Windows XP