I haven't been using my PowerBook for a while, so I've decided to fire it up and it's really nice. I've noticed two strange problems, however; first of all, the battery refuses to charge and stays at 0%. And another weird issue that my PowerBook has never exhibited before is that sometimes the screen just turns black, and refuses any input, even if I close the lid. I first thought that since the charger port was loose, the cable was slipping out of the port, but I realized that it's not really off since I see a faint horizontal line near the bottom of the screen when this happens, and I can hear a popping sound through my headphones (I usually have them plugged into it). I have to unplug the charger, plug it back in, and turn it on to get it up and running again. I've tried resetting the PMU, but it doesn't seem to have done anything. What could be the problem? Thanks.