Bigjoe,
Are you trying to completely restore the hard drive back to its original "out of the box" status or just wipe out the sites you have been to on the internet?
If you are looking for the first, then you will need the software that came with the computer (easiest) or another type of software,
if you just want to delete the history of where you have been then RIGHT click on the internet explorer icon on your desktop (assuming you are using IE) then click properties, then click delete files and it will run for a minute, then click on clear history and reply yes and the history for all workable purposes will be gone. Someone with even a little more than average computer knowlege can still find out where you have been, but they have to be looking and know what they are doing.
Hope this helps, if not then give me some more info on what you want and I can probably help.
penguinfan