I'm starting to wonder if my laptop's battery died sometime in the night. I remember putting it to sleep last night, but by morning the machine had shut itself off and needed rebooting. I figured I must not actually have closed it all the way, and so it ran itself down. But now, at least half an hour later, the battery still claims it's on zero percent, which would be improbable if everything were working the way it ought to be. At least the battery is easy enough to replace. I just hope that's as deep as the problem goes.