Webcam disconnected

Are you running windows? If so try "safely removing the hardware" by clicking on the green icon next to the time. After it says it is ok to remove it, unplug the webca and plug it back in.
If that does not work, go into control panel, system, hardware device manager and look under multimedia or scanners/camers for the webcam. Right click to disable. Then right click to enable again.
If it is still not working after that, I'd try removing the software you use and reinstalling.