Hi DaniWeb!
I was looking for a solution to a similar problem and see that I have found much more! What an incredible community!
Sorry to ressurect and old post but I wasn't sure where to post and this was the closest thread I could see to my problem. I just bought a sony vaio (windows xp) and hooked up my Logitech Quickcam Fusion web cam. When the cam is plugged in there is no sound on my laptop at all. I-tunes won't play and I can't hear other people caming me. I can see them and they can see me. They can hear me but I can't hear them. I can hear others fine and hear I-Tunes as long as the camera is not plugged in. Any help or pointing in the right direction would be great!