iSight HELP!!

I have a 17 inch iMac G5 with integrated isight. Suddenly I noticed that my video icon on iChat was not there and neither was my ability to preview myself. Photobooth too wouldn't recognize the camera. I tried rebooting and reopening and fixing permissions but nothing worked. It seems as if iSight has disappeared from my mac.

any suggestions???

 

Heres the update guys. Profiler was not recognizing it under the USB profile - which is not a good sign. So at that point I decided to put my apple care to good use. We did an SMC reboot (where you unplug the power chord for 15 seconds and then plug back while pressing the power) and viola! It worked. He said if it keeps happening then there is something physically wrong. But for now, to not worry about it. The truth is I had known about the SMC reboot and its magical qualities but I forgot to try it this time around..

Oh well, thanks everyone for the help.