I'm working on a student's Macbook (Black, 13", 2008-era) that is having a dim/black screen. When it powers on, we are barely able to see anything but you *can* see enough to maneuver around a bit (finding the mouse is a bit troublesome). When hooked up to an external monitor, the external works just fine but the Macbook lights up bright for about 5 seconds before dimming once again. Moving the screen position doesn't matter so I'm thinking it's not likely the cable. I reset the SMC (based on some forum threads) w/o any success. it hasn't been dropped, banged, thrown around, or otherwise messed up. If I press F1 to dim it all the way, and then press F2 to brighten it, it lights up like normal for about 5 seconds and then goes back to being very dim. However, if I only press F2 once, it stays bright for a long period of time (or as bright as the first level of brightness is). So far I'm on almost 10 minutes without it going dark but it does seem to eventually go dark. Dimming it and brightening again brings it back but it does seem to be having less and less 'bright' time. Any suggestions on what to do next or what part needs replacing?