SigmaTel Sound HD Audio Codec will not install

[Guest]

Upgraded from XP Pro (audio worked fine) to Vista Business. SigmaTel audio
driver will not install. Got message from 8007000D from windows update.
Downloaded latest Vista driver from Intel site and tried to install. Got
textbox:
"Device Obj not present". Added a soundblaster Audigy SE (PCI) and tried
to install latest Vista driver and got the same result.

For earlier OS versions, there was an issue: KB888111. Is this related?
What must I do to get my audio working?

 

[Guest]

I did not think that the Sigmatel HD Audio codec was compatible with Vista.
I know that when I ran the upgrade advisor it told me that it would not work
with Vista. Doesn't Vista have an HD codec "built in" to the OS?

 

[Guest]

VIsta does have an HD Codec, I think. Windows update finds one, but it gives
me the message described above. Windows update says I need it installed.
Because it did not work on installation, I uninstalled the one from XP, and
tried to update again. I get the same problem with both windows update and
the Intel Vista driver.