Just thought that I'd note here that I had a great amount of difficulty with my sound system in Windows7, all because of the #1 reason for electronics issues: the wire wasn't plugged in(at least not correctly).
The plug used for my headphones goes in a different slot for Windows7 than it does for WindowsXP/Vista. This might be (probably is) because of different audio drivers
, but if you're able to install the drivers but no sound is coming out of the other end, try all the slots. For me it was in a place that I've never inserted anything before, and I don't even know the name of the jack. I'm sure if I looked into it, it would make sense though.