The game is made mostly on Windows 7 64-bit, so I always find it a bit amusing when people think THAT is what is causing their issues with the game. An OS that is a bit of a strange beast however is Windows XP 64-bit. That is a rare monster that should not be alive...
Cool, I have not tried 8 yet, so that is interesting to know.
For the OP: I run it on Windows 8 CP x64 without any issues.
Cool, I have not tried 8 yet, so that is interesting to know.