Maybe it's just me being skeptical, but the number of times I've heard the stories regarding "I've lost my admin password/bought a second-hand laptop/got a friend who forgot all of his passwords/need to desperately retrieve a file from the college computers and need to break in" are too numerous so I've built up an immunity to them. It also didn't really help when you used the phrase "break into" either. I'm sorry if this is genuine though.
Do what kainashi said, and reformat the hard drive by booting from a DOS boot disk (or similar alternatives) and typing "format c:". It'll get rid of everything on the hard drive and let you make a nice clean start.
