Feedback in Ventrilo

I have been having this problem for awhile. Looked all over the place for an answer and can not find one. The problem im having is I can talk in ventrilo just fine. But when someone else goes to talk when i am, They hear a really loud annoying noise and get a lot of feedback. Also if i have music playing, they hear it as if my Mic is going through my speakers. I have the ports all in the right place as it says when i first plug them in. On my Cpu i use Realtek HD Audio Manager. This realy doesnt help when playing my games b/c i cant talk. I did just buy a brand new Mic and still having the problem. I never had this problem before i re-installed my computer.

Thank's
WhyAMIHere