sound but no pic when i try cam 2 cam

[chatters]

Hi

I am having problems on the site when i try to cam 2 cam with members, i can do shows for them no prob but wen i try to go two way all i get from them is a black screen and if i am on another members site and they invite me to c2c all they see is a black screen but they can hear me though.
Can someone please help me i have tried so much maybe my comp or graphics card not good enuff or not enuff memory just guessing my comp prob.

Regards
chatters