I'd like to know how to do this as well, but not sure if it'll fix the problem I'm having.
Issue: Since installing Windows 7 this week, I can not get VoIP working in a game(Battlefield 2). I enable it in audio options, but as soon as I join a server I check the options and it appears to have disabled itself. I've never had this problem with XP. I've tried many solutions, and the latest I've heard was to try and lower hardware acceleration for my video card(why they're related I'm not sure), but however I can't figure out how to do that as it's greyed out in the Troubleshooting tab and I can't figure out how to do it in nVidia Control Panel.
Hoping someone can help. Here are my basic specs:
Athlon X2 4800+
4GB DDR2 memory
nVidia Geforce 8800GTS
Windows 7 64bit