With Nvidia cards if HDMI/DVI is connected to a "Audio capable" HDMI Input. Analogue audio is totally locked out 
Here is a Fix, and link which links the original article (off line atm)
http://hardforum.com/showpost.php?p=1038495309&postcount=438
This has been an issue for me for a while with Nvidia and the muppets allow turning off HDMI audio in control panel but it does diddley squat !! and normal analogue is still disabled
Sure it will help a few out there
Here is a Fix, and link which links the original article (off line atm)
http://hardforum.com/showpost.php?p=1038495309&postcount=438
This has been an issue for me for a while with Nvidia and the muppets allow turning off HDMI audio in control panel but it does diddley squat !! and normal analogue is still disabled
Sure it will help a few out there