Hi - Ive just upgraded the processor in my iMac 4 from core duo to intel core 2 duo - I done this so I could upgrade from Snow Leopard to Lion - when trying to purchase the ne OS from App Store I getthe message : & "This version of Mac OS X 10.7 cannot be installed on this computer." - I have run disk utilities and no problems with HDD - I have enough RAM and also enough free space - can anyone offer any ideas as to where the error is - why doesn't the error message come with details or is there a way to find the cause for not being able to install Lion?