My son just bought a used computer from a "friend of a friend". It has a copy of XP Pro on it but I don't believe its a legit copy. It won't let SP1 download so it may be one of those "corporate" copies that were around when XP first came out. Anyway, I'd like to help him get a legit copy as he's away at collage and he needs to have all of the latest updates from MS. I've found the following academic XP PRO Upgrade but I don't know if I can use it to "upgrade" from from XP Pro to XP Pro. Any ideas if this would work? Since he is a student, he qualifies for the academic pricing. Thanks for your help with this.