Vista - Problem with Video Call

Hi,

I encountered this problem with Windows Live Messenger. I tried starting a video call with my niece overseas, there was this ringing tone. But we cannot start the video call as my laptop will just hanged with the ringing tone still going on. I asked my niece to call me instead, there was this ringing tone but once awhile my laptop hanged.

I had checked my firewall, the windows live messenger was not restricted. When I started to share the webcam, it was absolutely alright. I can see her, she can see me. But my laptop will just hang whenever we tried to start a voice call. Laptop just hang with the ringing tone going on.

What could be the problem? Any advice or troubleshooting I can do to dissolve this technical issue?

Thank you very much.