I bought a dell computer that came with Vista booted up on it, aswell as the installation disc just in case I need to reformat my computer - which I ended up doing a while back. Anyways, my buddy is building up a computer and needs an OS for it - if I popped in that installation CD in his computer an booted it up using the serial number provided - would that work? Or would there be any chance of screwing my registered Vista over or something like that?