Greetings, I've been wondering this for awhile and wanted input. A few years ago I bought Win7 Home Edition complete with it's own key. Then I bought more memory (more then the Home edition would allow actually) so I had to update windows to a new version of Win7 to make use of the memory. Now during this process Microsoft sent me a new Windows key for Win7 Ultimate edition. Ok so @ this point do I have the orginal key for Win7 Home & now a key for Ultimate? Thus having 2 copies of Win7 - Home/Ultimate? Also to further muddy the waters I upgraded to Win10 awhile back which if I remember correctly stated that the Windows key I was using was now a Windows 10 key. So do I have 3 copies of windows to play with? Can I install Win7 Home on another pc using the orginal key? Then build another pc using the Win7 Ultimate key? Yeah I'm pretty confused by this point.