I've just set up a new Windows 98 SE / XP SP3 dual boot Athlon XP system using an Aopen AK77-600N mobo, which has the VIA KT600 chipset. Everything went smoothly, all drivers installed fine, device manager showing no problems, but for the life of me I can not get any sound out of the onboard AC '97 either in 98 SE or XP. I installed the VIA Hyperion 4in1 chipset drivers first, and then the relevant Realtek AC '97 drivers (A3.45 for 98 and A4.06 for XP). I've got Directx 8 in 98 and 9c in XP. Realtek Sound Manager shows everything fine hardware wise, I'm not getting any errors anywhere. Just absolutely nothing out of the audio jack (yes, I've tested other devices on my speakers of course, all fine!).

Before I assume the jack is broken and just give up and just order a Soundblaster Live! card for this machine, does anyone have any thoughts or suggestions to try?