Can't Re-Enable Camera

Hello everyone, my name is Morgan and I need help:

The other day I unchecked the menu item "Camera Enabled", with the intent of temporarily disabling my webcam (the built-in iSight). It did indeed disable my camera. Well, I can't recheck the "Camera Enabled" thing -- it is greyed out and utterly un-clickable. I cannot re-enable the camera. Also, the same thing happened with screen sharing. I disabled it, and now cannot re-enable it.

I have tried re-installing iChat from my installation disks. Didn't work.

Following the advice of an Apple Support article, I tried resetting my SMC. Also did not work.

On the menu, instead of being able to click on Video between Buddies and Format, my option now is Audio. In iChat Preferences, it says "This computer does not support video conferencing" when I click the Audio/Video tab.

I am fresh out of ideas. Does anyone know what I did, and what I can do to undo it? I am about to throw my computer across the room, I am so frustrated. I use video-conferencing and screen sharing for my photography business, and I really need it to start working again SOON.

Thank you so much!!

Message was edited by: morgankrehbiel
Whoops I accidentally posted twice -- sorry!