someone in my area is selling an ibook on craigslist for cheap. the only problem they state is this... "There is one small problem with the laptop though. For some reason when the screen is opened past 90 degrees the screen goes dim. I just close back to 90 degrees and it works fine. The computer itself does not turn off when this happens." whats wrong with it? too much trouble/money to fix? its a 700mhz ibook g3 14" 20gb, 256ram going for $250. worth it or not?