I upgraded my win 7 to win 8 pro on a 32 bit laptop. I selected the DVD option rather than direct download of ISO files. I recieved both 32 bit and 64 bit versions in two seperate DVDs from MS. My problem is the product key they provided works only with the 32 bit version. Do I have to buy a seperate key to use with 64 bit win 8 pro? I will only be using this key on one computer.