Not quite sure what you want to do. Are you asking if you can install a copy of windows on a computer using the an activation code that you have already used on another computer? If so, then the answer is no, you can't do that. The windows license specifies that a copy of windows can only be installed on one physical computer at a time. If you install Windows on another computer then you have to buy a new activation code to activate windows on that computer. The rule applies to all copies of windows regardless of the version. However, if you are migrating to another computer with a retail copy of windows(not OEM), then you may be able to call Microsoft and get them to activate your copy of windows on your new machine while...