For thefonz: I'm sure Patio will likely respond to this himself - but I took his message to mean: to reinstall an upgrade to XP, first boot the XP upgrade disk. Then, at some point during the reinstall process, the user is prompted to insert the original ME disk, simply to confirm that the upgrade to XP disk is legitimate. After confirming validity of the upgrade from ME, I assume the user will be prompted by the system to remove the ME disk and reinsert the XP disk.