Lost onboard sound GA-MA785GM-US2H

[airbird]

I was using GA-MA785GM-US2H motherboard for 4 months with no problem but after I installed a gigabyte gv-r467zl video card w/ hdmi ( resolution was crappy took it out) the onboard sound was completely gone. I reinstalled hi def sound drivers but nothing, updated bios but nothing -called gigabyte and they will issue me an RMA but I want to know how this could happen. Why would just trying a video card cancel out the onboard sound for good.

 

[bilbat]

My guess is that the vid driver install somehow 'defaulted' the sound output to the HDMI, and did it in an 'inobvious' place, or one that no longer exists with the driver removed. Assuming your board has one of the pretty much standard RealTek CODECs, I'd try reinstalling the RealTek driver package, and, once the RT tray icon appears, right-click on it, which, I believe, 'exposes' the active/default sound channel selections...
I am without my usual complement of MOBO manuals, so am not sure which CODEC your board uses, but it's likely covered by these driver packages:
http://www.realtek.com.tw/downloads/downloadsView.aspx?Langid=1&PNid=24&PFid=24&Level=4&Conn=3&DownTypeID=3&GetDown=false