I remember witht he old like win98 and 2000, even Me, it didn't matter what computer you used the key on or anything. But with xp does it matter? I've had a few times where it tells me that the key was used too many times already or something like that, but I took a key from a different copy and used it, and it worked, I've done this a few times. Now I have this new OEM version of windows xp home. Can I use that key on any machine? Does it matter? I need to reinstall windows again, I'm doing a repair, will it even ask me for a key? Maybe not right?