Problem with microphone!

[MunkeN]

I have a problem with my new headset (creative HS-900).
When I speak on Ventrilo and run Winamp at the same time, they hear both me and winamp.
Same if I'm watching a movie/playing a game/whatever.

Anyway of disabling so they only hear my voice?

Everything was fine with my old headset.

Some settings: http://munken.nbounce.se/ljud.jpg

Some people say it might be a soundcard setting named 'What you hear', but I can't find that @ nForce.

I'm using nForce4 codec: Realtek ALC655


Regards,
MunkeN.