Oovoo Why Cant I Use My Mac Built In Camera Oovoo Help On A Mac Laptop PLEASEE?

Oovoo help on a mac laptop PLEASEE? - oovoo why cant i use my mac built in camera

Although I installed my ooVoo and everything on my Mac and I have a video, filmed with my friend but couldnt see me, so I tried my video connection test, but for this you need to leave your video on first connection . So I tried it and after a request ooVoo suddenly everything froze. I have tried to quit, but the strength of the menu does not appear to the closure force. I have also tried switching off my Mac, but it does not work, unless ooVoo eiether first, I can not do that !!!!! hellpp meee pleassseee!