I have the messenger, a Logitech zoom Webcam with micro.  Each time during a video webcam transmission with my friends - my friends hearing a loud whistle. Like a accustic feedback. I already tried and each time with different friends and it is the same.  I adjusted all audio and micro settings to minimum.  Did I'm guilty - it is the error by me?
I must still supplement I have a old PCI TV Card, the audio from the TV Card goes into the soundcard. From the soundcard goes the sound into my stereo hifi system. If i plug a headphone in my hifi system, my friends didn't hear the loud whistle and everything is ok. Did someone have the same problem or a solution?

P.S. Sorry for my bad english, this is not my motherlanguage!

Hhhm, I have a diferent set up to you, but I have to mute my microphone to get rid of a loud whistle.  The other person can still hear me fine, just does not come out of my speakers anymore.

Does MSN Messenger use any kind of noise cancelling technology?  I have seen this before with noise cancelling, that is why you should try turning ya mic back up and mute it instead.  It might help.

That's just feed back from the cam, just turn down your speakers or the other persons speakers

Hi and thank you for the answers!
For the first, sorry for my late answer!
I adjust the volume in the Speaker-settings from Windows XP and on my HIFI System. Now it works, so the reason about the feedback, was the settings from the speakers - the microphone is too sensitively and I adjust now all on minimum.
Thank you very much for your answers.

Elena