Asus P4SD-LA - Audio Problems

Hello All,
First let me thank you for the countless problems this group has helped
me fix while I have been lurking. I figure it's time to de-lurk and ask the
folks who know. I have been pulling out what little hair I have left over
this one. I have 3 new HP systems - they all use the Asus P4SD-LA mobo. At
my wonderful bosses request, I wiped the factory installed OS and installed
WinXP Pro. Everything works wonderful except I cannot get front channel
audio on any of these units. I have gone to Realtek's website and gotten
Driver v3.49 for the onboard ALC650 - AC'97. It installs pretty and no
problem in device manager. Looks like it should be playing audio just fine.
HP's been NO Help, Asus won't talk to me at all because it's an OEM only
board, Realtek's ONE US based tech support guy is in TAIWAN this week!!
Before you ask, I have checked windows volume / slider setting, BIOS
version and settings (Audio is Enabled), Different speakers and
configurations, and I have re-installed the factory installed OS with CD's
HP sent to me. Nothing works for front channel audio. I can get rear channel
audio all day. :-( Help!

Thanks,
Karl North
Systems Admin