Windows7 and Vista's driver model is exactly the same. If it works in Vista, it works in Windows7 -- for the simple reason that the code is exactly the same and hasn't been changed.
Windows7's optimalizations are done in a different area.
Just get your games from places l like play.com, playasia.com or gamehubs.com.
I occasionally get something from steam if it's really cheap, but most of the time it's not worth it anymore.