Can someone help me fix my microphone problem

Hello,
I recently just formatted my PC, and everything seems to work fine, except my microphone.

The headset still recieves audio, but when i speak on ventrillo, my mic seems to play the sounds i am hearing to the people listening, instead of my voice. And on msn, there is just nothing.
I have looked around all over windows and in the volume controls etc, and the solution is just beyond me, i am honestly baffled.

I have looked on internet set up tutorials but they seem to show options that are not in my options or greyed out so i cannot alter them.
e.g:
one tutorial i saw, had an option called "microphone" in the volume control tab, but the cloest thing i have to that is "MIC volume" which is greyed out to me, i can't alter it in any way.

Failing to solve the problem, if there is a way to restore the default audio settings, that would also be helpful, as i have changed and ticked and unticked so much i have lost track on what i have changed. I think i may have just created new problems for myself.

Any help is greatly appreciated