Web camera audio/video IM problem

[mnthought]

I am an old guy trying to successfully IM with my son so I can see and hear my new grandaughter! We both have the logitch communicate stx web cameras and XP. Using AIM, when I try to communicate with them, I may see them and hear them while they can see me but not hear me. Or it may be some variation of that problem. Any ideas? I am currently stumped!