How can I get My 5.1 surround speakers back working on my On board sound chip?

[Windows Central Question]

I did a clean install of Windows 10 build 10162, and my AMD HD7900 Card drivers updated, since then I cannot get any sound from my Via VT2021 HD sound chip, it only plays through my HDMI Lead to my AOC Monitor speakers. I cannot stand the tinny sound. Nothing so far has worked as i've researched it Google. PLEASE help me thanks
Think this is known as HDMI passthrough, but I prefer my speakers to give sound not my monitor. Using Gigabyte Z77-D3H Mobo, with Intel I5 16Gb memory.