MacBook :: Built-in Camera Works On Skype But Not PhotoBooth

I have OSX 10.5.8. In the past, I was able to use PhotoBooth, but now when I open it, all options to take a photo are grayed out. The screen, where, I believe, previously I'd seen whatever was in the built-in camera's lens (generally whatever I put in front of the screen to photograph), I now see all black with a white camera icon crossed out. Skype works fine though. When I try to load iChat, it crashes unexpectedly. For clarification, I'm using the built-in cam and do not have external camera hooked up to it. I don't really care about iChat, which I never use, and am very, very glad that Skype, which I do use, is working.  However, I would very much like to get PhotoBooth working.

Info:
MacBook (13-inch Early 2008), Mac OS X (10.5.8)