A friend of mine just dropped off his computer and wants me to install XP Pro. It now has XP Home. My first thought was to take his drives out (2 drives in RAID 0), format them on one of my computers, re-install into his computer, and then install the OS. If all that isn't needed I'd just as soon not spend all the time required to do all of that. I've never tried to install an OS over an already installed OS..... What's the best way to do what I'm trying to do?