NVIDIA GTX460 'no audio devices installed'

[THX-UltraII]

Hi guys,
I just bought a GTX 460 card and want to use the high res. audio (DTS-MA/TrueHD bitstream) from the card. I tried to install and reinstall the NVIDIA driver over and over again but I just keep getting 'no audio devices are installed' under sound options. The strange this is that the NVIDIA control panel lets me choose my receiver (Onkyo TX-NR5008) under the setting 'setup digital audio' option 'HDMI'. At my Device Manager there is shown 4x 'NVIDIA High Defenition Audio' under 'Sound, video and game controllers'......

Setup:
Asus GTX460 with 295.73 driver (also tried the latest)
ASrock H61M-ITX board (http://www.asrock.com/mb/overview.nl.asp?Model=H61M-ITX)
Windows 7 64-bit with SP1 and all the latest updates
Latest DirectX version
GTX460 connected to my Onkyo TX-NR5008 AVR with mini-HDMI->HDMI cable
Onboard audio disabled in bios

If more information is needed please let me know.
Hope someone knows the solution for my problem.
Thanks!

[aedipuss]

unless you have a separate audio card i don't think the onboard audio should be disabled.

[THX-UltraII]

? why would I want to turn on the onboard audio of the MB if I aint going to use that at all? A GTX460 has build in (HDMI) audio.

[mh2360]

aedipuss may be correct.

The audio hardware on a GTX 460 is only used for HDMI output, the onboard sound is still used for analog output to speakers or headphones.

Rather than completely replacing the onboard sound, the GTX 460 works along side it, and because you disabled the onboard sound, your PC may be confused into thinking it has no sound card at all.