Can't set HDMI audio as default

[BDani]

Hey guys. I recently connected my HDMI output from my LCD to my PC.
I have Nvidia GTS 250. I looked around for some tutorials and solutions to my problem but non of them seem to work since they all say the same thing: set the HDMI as default in my audio settings. I tried but i couldn't do it because it wont let me. I open up Control Panel> Sound and I can't seem to find anything but my SPDIF. When I click on it, the "Set as default" button is not availble. I can't press it. Nore when I right click on it.

I had Nvidia Geforce 8400GS. Nothing. Then I updated to the latest drivers. NOTHING!
So I installed my old GPU, Nvidia GTS 250 and also installed the latest drivers form their website and still nothing!
I tried to remove and reinstall Realtek HD audio drivers and still nothing.

Funny thing: When I right click my SPDIF option I see "test sound" and when I click it I can see the green audio thing goes up at the system tray.

Also... Here's a picture from my device manager:
http://i40.tinypic.com/24evprd.png

Im hopeless I have no idea what to do.... I use Windows 7 64 bit.

please help

 

[fireberd]

If you are connecting the OUTPUT of the LCD TV to an HDMI port on the PC it won't work. The HDMI on the PC is an OUTPUT only, not an INPUT.

Maybe something was lost in the translations to English?