Hello, I have the legit version of Windows 7 32 bit, it has 2 cds inside, i presume one is 32 bit and the other is 64 bit. I upgraded from windows xp 32 bit. Is it possible to install windows 64 bit using the 64 bit cd? or could I download windows 7 64 bit, burn it to a cd and install it using the license key I have? Or would I have to buy the full upgrade to use 64 bit?