How to Reformat Hard Drive?

First thing is your going to need your operating system disk to format it. Shut the computer down. Turn it on and place the disk in the CD ROM bay. Close and wait for it to ask you how to boot. Select the run the disk option. The repair software will run a few things and the ask you what to do. Find the option reinstall windows on a clean partition. That should do it! Look here for more information: