make sure all the new drivers are installed. My last board M3A32 always had issues with the onboard sound, the auto device detect was a pain in the butt. after weeks of headaches I bought a USB headset and Disabled the on board sound card in bios . No Speakers but all I did with it was Gamming so the headset worked wonderfully
1100 BE Liquid Cooled, CHV, 16Gig Corsair Vengeance 1866 @ 2032, two ASUS ATI 3870's liquid cooled O.C.ed to 890Mhz, 3 Velociraptor 500G in raid 0, ocz SSD boot drive, 1200W Thermaltake P.S.