Windows 7: no sound at all, all drivers updated

hi,




a few days ago, after a restart of my PC, I didn't get any sound at all, and still dont get it.
all my drivers are apdated, realtek, motherboard drivers, graphic driver...
i've tried uninstalling and reinstalling realtek driver and software
and - as you can see in the picture -
windows media player is playing a song. in the "sound" menu (top left), the speakers (defined for realtek hd audio) are also working, the geen bars go up and down. in the device manager (down left) i have realtek driver, updated. and all nvidia drivers (as it always been, and also i checked another pc and has it too). realtek manager works fine, recognize when i plug into the front or the rear jack (using the green one at the rear), everything seems ok. but (!) the "volume" menu (down right) doesn't have a green bar that goes up and down, and - I dont hear any sound at all...
tried connecting speakers to iphone - the speakers are fine, works well.

what can i do now?

Is the audio driver you installed is compatible with your audio hardware you use it ?
Please update manually don't use software update driver to update your drivers
It may cause incompatible drivers sometimes
Are you using external speaker ?

i'm using the on-board audio, on a Gigabyte P67A-UD4 motherboard using ALC892 audio codec, so I downloaded the realtek driver from gigabyte website, according to these specs. and when I open realtek manager, and "about", I see that it is for the ALC892 audio codec.
i've tried uninstalling and reinstalling the drivers. didnt work.
tried the new 2.68 realtek, didnt work.
fried system restore, didn't work.

maybe i should open up the computerand look for a loose wire or something?
the problam started a few hours after I inserted another graphic card, maybe i touched something...

removed that graphic card - just in case - didn't work...

-- update

seems if I connect my tv, using hdmi, to the nvidia graphic card, i can use that as the default playback device, instead of the speakers. and that works.
but i still want to use my speakers!
i gues that means the problam has something to do with the driver or somwrthing blocking that driver, but what can it be?

what now?