1.83Ghz 512MB Ram I dont use battery a lot(probably about once a week) but the last time i did(and the few times i tried it after to see what was wrong) it would work for about 15 minutes, then do what seems like a hard shutdown, as if i held the power button down. Then after that i can boot it up it makes the startup sound, then goes to like a dark black screen that seems to flicker for about 5 seconds. Then it shuts off again and cannot be booted up until its reconnected to power. When its reconnected it boots up normally(although the apple logo screen does seem to take a few extra seconds). The only other weird thing is after i boot it up connected to the power, the next time i unplug the power cord the computer automatically goes right into sleep mode, i just have to click to get it out, but its still a very weird thing.