I had 2 Windows 7 pro discs, but one of them was burned (as in turned into charcoal) and was never used. Now I came into possession of a Core 2 Duo HP laptop that is without an OS (it has a restore partition but since it was originally packed with Vista I'm trying to avoid it). I'm wondering if I can use the other Windows 7 disc I have but use the key of the one that was never used (I have the key of the burned one). Is this legal? Can it be done? The two discs were of the same version. If it can't be done I'll install ubuntu on it, but I would like to also have Windows 7 (as long as it doesn't cost me a dime) so that it can be used as a house laptop when I go to grad school in a couple months.