Photobooth works for one second, then stops.

It used to work. Like all the time.
I'm using a Logitech camera, which works fine in Skype and iChat. But when I open Photobooth, the camera turns on, works for a period of one second, then it stops. If Photobooth is open but behind another program, when I switch back to Photobooth I get a quick one second refresh of the image before it freezes up again.
When I Apple-T, I get the 3-2-1 countdown, then it takes a picture of the frozen image and adds it to the previous photos.
The camera is plugged into a USB 2.0 card I installed last year. Everything else on the card is working. I've even switched ports around, and everything is working (which makes sense, because the camera works in Skype and iChat.)
I was hoping to use the video function to record some voiceover stuff and then transfer the audio into iMovie.

I would try Repair Permissions.
This is done with Disk Utility found in Applications/Utilities using the First AID tab.
If that does not work I would Reset the PRAM
Hold down AppleALT+PR keys on restart until you have three start up bongs.
If that does not work I would download and install the Combo Installer of the OS level you are up to.
10.5.6 COMBO is here
9:00 PM Thursday; February 26, 2009