I have a tyan s2875 mobo using the integrated sound card. There is more info on the mother board found here.
I believe its a realtek ALC655. I have the win 7 64bit build 7100. Dual opteron 242 with 2 gigs of ram an ati radeon 1550 vid card. Thats all i can think of.
Ever since i installed win 7 I have sound for maybe 15 second while on sites like youtube. I still have sound on my computer, can play system sounds or open an audio file or something like that. Just no internet sound until I restart. I have tried to find different drivers but so far all that works is what windows installs with it.