Originally Posted by sherwood
if you try and register it they know, but besides that MS has no clue where that computer is, all it knows is 2 different computers are using the same windows OS.. and MS has no way other than somthing like windows update to find out where the original computer is (the second computer on the other hand is easier to find...)
IP's, with the help of an ISP, can easily be traced back to a time and a user.
MAC address is passed onto the internet with each packet.