My mom's iBook G3 has recently started doing this thing where its screen goes dark if you bend it back far enough. Right now the furthest I can open it is so it's at a bit over a 90 degree angle, or else it'll go dark. Does anyone know what could be causing this? It's spent most of its life on a desk, and has never been dropped or anything, so I don't think that anything could have broken. Any ideas? Thanks!