I have 2 copies of Win 7 Home Premium Family pack. 6 licenses total. Here is what you do... install win xp or vista on the new hdd first and then when you install win 7 delete the partition win xp/vista was on... if you have a hdd w/ another OS on it copy that image to your new HDD and install Win 7 on top of that remember to delete the original partition on the new hdd to wipe it all clean. The install disk is just looking for evidence of a previous install. once it sees it you can safely wipe that install off the HDD.