you know i had the same problem with one of the pcs i was fixing last week and it was with the ac 97 audio to.
It was what came up wen i ran everest AC 97 Audio something
I cant remember witch driver but i was able to get a version of soundmax to work it took me hrs trying different drivers and i left the exe in the pc i was fixing i dont have it anymore.
i found it by a luck to i spend hrs looking for drivers none worked but that one and i really cant remember were i got it but i know it was a soundmax driver
try this see if it works
is for ac 97
VIA Vinyl AC'97 Codec Combo Driver - Free software downloads and reviews - CNET Download.com
if u cant get it working u can alway ask ur friend if he wants a new soundcard u can get a decent one high def audio for like 30 bucks or maybe less