If you installed XP over 98, that registry entry is gone. I'll also add, the last thing you want to do is an upgrade install from 98 or ME. I've done many XP installs, and upgrades from 9x are notorious. You can, by the way, do a full install with an XP upgrade disk. Boot to the XP CD. When you get to the point where XP tells you it can't find a previous version, insert your original 98 disk. XP will move forward from that point into a fresh, full install. You will not need to know your 98 key number.