I've got a ? for anyone whos a comp genius.

How do you completely wipe windows off a computer, so i can reinstall a new operatng program? I was told you open it in DOS or some crap, but if you dont save certain files your CD rom wont work or something, idk but I need help, so if anyone knows, id appreciate it

http://www.dban.org/

How do you completely erase everything off a computer and keep the operating system (keep windows 7 on it) and make it as if it's a brand new computer?

Simple, pop the disc for your OS in, start it up and when it gets to the partion screen, delete the "C" drive and reparation it, there you go everything is gone, fresh start.