So My question is can I take an existing hard drive out of one computer and put into a different computer if it has an OS on it? I am giving my wife my computer since I have a new but I don't want to have to transfer her stuff over to her new one so I was thinking it would be easier to take her hard drive out and put into the new one but it has an OS on it. It would be a secondary HD and would not be the boot drive so I didn't know if it's even possible. The computer all ready has main drive with Windows 7 Ultimate that works great. I have her files backed up and could do it that way but it's a good drive and need some advice. Thanks for the help everyone.