OK this is killing me. I have the same audio device that you do. So I killed mine to see what would work. I found that an older version I got here
worked. It is like 3 years old but did the trick for me.
This is the driver name:
Realtek AC'97 Driver V5.10.00.5750 for Windows 2000/XP(WHQL)/2003.
I put my audio at risk ;-) for you so I hope it works
Check add remove programs and make sure you uninstall any other instance of the AC'97 drivers if they are there.