No sound after Moving GPU from secondary PCIe (x4) to Primary PCIe (16)

[AbuRyu]

CPU FX 6300
Mobo M5A97 EVO R2.0
GPU AMD 7870 XT
8GB ram
Win 8.1

I have checked BIOS and the onboard sound is enabled
When a video/ sound is playing the green meter on the mixer bounces up and down which shows that a sound is being generated.

Does this mean the problem is the connectors? I have tried both front and rear connectors.

Also I'm unable to use mics either.

The only thing I have yet to try AFAIK is putting the GPU back on the original PCIe slot.

Am I missing anything else?

Update:
With GPU in original slot still doesn't work.

I've noticed that when unplugging devices from the rear connectors, I get a pop up to confirm its been plugged / unplugged. However not the case with the front connectors, which seem to show up as having a headphone and a mic connected even with nothing plugged in. I'm going to disable the front connectors and see how it goes.

[mark_a_scott]

I wonder if you have HDMI enabled as your default audio device? I had this on my PC and I ended up having to disable all except the sound card