You need to provide some information. Like whether it's integrated sound or add-on pci/isa and what pc system and/or motherboard it came pre-installed in. Otherwise, with the vague info, all I can suggest is the visit the
Via website
Note: AC'97 is only a term... it's not a sound chipset or manufacturer. AC '97 is a term adopted by Microsoft in 1997 pertaining to sound standards. Most (if not all) current sound chipset makers have "AC '97" compliant sound devices. There are only a few sound chipset makers in the world... amongst them are Realtek, Cmedia, ADI Soundmax, and Sigmatel. Chances are good that your's is made by one of those manufacturers... but we need to know which one.