Ack!

I recently formatted, installed all the drivers as usual, now I noticed I'm getting mic feedback through the speakers (ie Hearing my voice, popping ect) Headset is Sennheiser PC150, It started doing this after the format, and I've tried just about everything, please help. :/

I do have another set I could try, but I dont think its the headset

Here is a simple question. Have you tried muting the mic or moving the slider all the way down? Disable mic +20db boost?