Hi guys, as you know the 1 year free upgrade time to Win 10 ends in half a year. Half a year ago i used one windows 7 license key and upgraded it to win 10 on my desktop pc. Now i have 2 other keys which until now havent been used on any PC to upgrade to windows 10 at all. So my question is can i install those 2 keys with windows 7 and upgrade to windows 10 on the same single PC? What irritates me is the Hardware ID validification. Will i be able to use these upgraded keys on another pc in the future (after the free upgrade period) for installing windows 10? Or is the free upgrade 100% machine bound. I mean does it make sense to install the 2nd and 3rd key and upgrade each time seperately so that all 3 keys have been upgraded or does it not work because i did it on the same machine and the free Upgrade is 100 % hardware bound. All the Keys in question are german OEM keys. (GERMAN OEM KEYS ARE TRANSFERABLE TO ANOTHER MACHINE (BEHAVE LIKE RETAIL KEYS) NOT LIKE IN THE U.S. WHERE OEM KEYS ARE NOT TRANSFERABLE AT ALL). So you could consider my question as if i had 3 retail keys and 1 pc and whether it makes sense to upgrade all 3 time after time or not because its hardwarebound.