M3A78-EM - No Audio

I've got this motherboard and all attempts at getting SPDIF audio out are negative. In fact, the root cause is, I can't get WinXP to recognize any audio device. I have made repeated attempts at downloading the latest Realtek HD Audio driver, but there's no evidence that it was installed and selected as the default device driver.

I have enabled the BIOS for HD Audio. I am NOT using the HDMI out, as part of the onboard video, as I'm using a separate PCI-e Radeon graphics card. I'm just trying to get the Realtek driver installed and functioning. In fact, normally, there's a little Realtek audio applet that's installed too. But nothing shows up in the control panel. Why does WinXP (SP3) insist on saying there's no audio driver? I updated the BIOS tonight, reinstalled the chipset drivers, Realtek LAN driver, and downloaded the latest Realtek HD Audio driver from the ASUS website and installed that. Nothing! Is there some other setting in the BIOS that needs to be enabled? What am I overlooking - short of bad audio on the mobo?

Help.

redjr...

this is basic problem in m78 and m68 mbds this is due to hda chip pls replace it with the vendor if it is in warranty or send it to service centre for repair.

Oh great! I only discovered this after I removed a PCI sound card. Now what to do? I guess it's still under warranty, but I'm sure Newegg won't take it back. I'll contact ASUS to see what they have to say. Thx,

redjr...