Microphone/possible motherboard

Hi, I have a problem with my >USB C-media headphones<, the problem being the microphone. Im not sure which section of forums to place this as it could possibly be a hardware problem with motherboard, as this problem only occured after i bought the new motherboard - >DFI 790gx m2rs<, I placed it here because I am using vista 64 ultimate. The problem is that the microphone is stuck in stereo mix - i can only play music or sounds that are played on the pc through the mic, it wont pick up my voice. I've tried countless driver reinstalls to no avail. I have tried both the USB and onboard audio jack ports, neither working. The onboard is Realtek HD, something to do with azalia - which i also disabled in the bios to give a go but didnt work. There is no option in the sound control panel/recording or playback to disable stereo, or even tbh change microphone settings apart from the microphone volume and microphone boost which do absolutly nothing. So yeah, im stumped and hope someone can solve this problem It was working before i got the motherboard, but i reinstalled windows at the same time as replacing the board so maybe a setting was possibly lost.

>John