OK, I am pretty sure that you will need AC97 drivers for the audio driver
Go to link below and click the Click here to Download* (in blue) about half way down page
-After you click the link it will take about 10 secs or so for the download box to come up - Save to your hard drive
Once downloaded:
-right click on My Computer and choose properties
-hardware tab and then click device mgr
-Now in device mgr, right click on Multimedia Audio Controller that has yellow mark next to it and choose Uninstall and say OK
Once uninstalled, close device mgr window
-Now go to where you saved the downloaded file below and run the program and follow instructions
-Restart computer
Now check your sound
VIA AC97 audio driver 6.80b download