When changing over from Vista 64 bit to Windows 7 64 bit was easy except for iTunes. I did a lot of digging and I found the issue posted all over the web with no real fixes. Well here is how I fixed mine.
Now first I did go from Vista 64bit to Windows 7 64 bit. Once I reinstalled itunes I simply just had to go into it click on "Store" up in the upper left hand corner and then to "Authorize Computer". Now for some reason it will authorize it as if its on the a different computer (it will say its the second computer)