Win 7 changes forgets SOUND configuration on my HTPC

[jserrat]

I have a problem with Win 7 sound.

My home built HTPC is based on Asus M2n-SLI mobo and ATI Radeon HD 5450 video card with HDMI out to Onkyo 7.1 receiver which passes video and audio via HDMI to Olevia 36 inch LCD TV. PC (ATI card)-- HDMI out --> stereo receiver -- HDMI out --> TV

The HTPC is never turned off. When I turn on the receiver and TV components to watch TV, Win 7 (Home Premium, 64 bit) will mute the system. I cannot just unmute.
I have to go into Control Panel > Sound. There I find only one option (expected): AMD HDMI output.

When I right click and choose Test option, it works just fine. I make no changes to the configuration and the sound/speaker icon in the system tray is normal. Then I open Media Center and everything works fine. When I'm done watching TV, I turn off the receiver and TV. When I start another session, the problem is back.

I did not have this problem with an older receiver but using completely different component connections. PC -- HDMI out --> TV -- audio out --> old stereo receiver.

Any help would be greatly appreciated! THANKS!

 

[jserrat]

Further research indicates that the HD 5450 driver is most likely the issue so I ordered a HD 6570 card. I'll get more power and features and hopefully I'll have better luck with the driver on this "mute" issue.

 

[jserrat]

Solution: I went to the BIOS and disabled the onboard audio. While the HD5450 video card driver was part of the solution, for other, mainly performance reasons, I ordered and installed an upgrade: HD6750. So far so good. The last problem to solve is the random reboot of the system due to some WMI event 10 error... but that's a different post.