No audio device after update

After downloading the security update and hardware update (C-Media AC97
Audio) yesterday, I no longer have audio sitting on my task bar. It shows
'no audio device' and C-Media cannot start. When trying to play windows
sound, I got error message 'Your sound card may be in use.' I thus rolled
back C-Media back to Avance AC'97. Although it says the device is working
properly now, other symptoms persist (no sound, no audio device, and sound
card in use...) BTW, I also tried restoration, but things get worse -- more
devices not loaded. Previous thread mentioned Vinyl'97 codec combo driver
(WDM), but I don't have that under Sound, video and game controllers. Could
anyone provide any advice?