Missing HD Audio driver

After one week with no sound on my Vista MCE I am starting to get a bit
frustrated...

I have the Intel 915P chip on a multicenter, and all drivers etc. were
proven problem-free with Vista.

But when I install I get the following:
- 10-15 unknown devices in Device Manager
- Found new hardware wizard from the hardware above (looking for HD Audio
Bus Modem driver!?!?!)
- No sound at all ("No digital input" on my speaker-system)

What I have done:
- Installed the new Realtek-driver
- Installed some intel 915p inf-drivers (chipset)
- Tried a lot of other things

But I do not get ANY further; there are no sound-device on my system...

Can anybody help!?!?!

Best regards, Henrik - Norwaii