I bought my disk from walmart and it was GOTY.
the problems are 1)product key wont work... i tryd switching I with 1 but even that despret move didn't worked out for me.
2) when i try to enter game it crashes right after new game option....
i dont really know if the 2nd problem is because of the 1st one but i really need help with this...
oh and it says the key is invalid not "in use" or something like that.

windows 7 home premium 64 bit and it is downloaded in the 86 bit program files...

thnx ahead...

just read through this forum. I'm sure you'll find the answer to your problem.