Hi,
Does the camera appear in System Profiler ? (Hardware > USB)
Does moving the hinge make a difference ?
(older versions had a Frayed cable through the hinge after prolonged use)
Later versions can have an issue with the cable going up the back of the screen becoming tight enough to loosen the end from the camer.
Odd thinks like gripping the screen top top steady whilst carryng the computer may effect this. (I would not and I am Not suggesting you pinch the screen as there is no measure of how hard to do this).
If it does not appear in the System Profiler try aSMC/PMU rest
9:48 PM Friday; September 2, 2011
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb( 10.6.8)
Mac OS X (10.6.8),
"Limit the Logs to the Bits above Binary Images." No, Seriously