Last time I upgraded a computer it would not let me use the same win7 disk I had. I mean it would let me install it, but not activate. Even though same name. Heck it was the same computer just upgraded a couple things. I called Microsoft and after awhile on the phone was given a different key to activate....what a pain in the a$$ that was. I sure did not want to run out and buy another copy of win7.(yes I know there are ways around this, but wanted to keep it legit)