I tried several times to buy the 'offer' Windows 8 upgrade using my older Windows 7 keys but was turned down every time because Microsoft must somehow know how old each pc is. I managed to be given a serial number from a friend who has just bought a Windows 7 laptop and who is not interested in going to Windows 8 and this worked immediately so I now have my desktop genuinely licenced. Now today I tried to use the same Windows 7 key to enable me to buy another offer licence but again Microsoft must know that the Windows 7 key has already been used for an upgrade so I got the 'Sorry but no' screen. Does anyone know if I use the original link sent to me by email whether it will allow me buy another offer licence using the same offer code or will I more than likely get a 'Sorry but no' warning because the offer code has been used before. Alternatively would I be able to use the genuine key on my laptop(s) as well as my desktop or would it not work. I did not know if it was possible to run my two/three pc's in the same household with the same genuine key ??