What it actually said was that the battery was low. She'd likely left it on overnight. I told her to reboot (she'd had log-in problems as well) and to leave it plugged in today. Somehow, she'd gotten 5 or 6 low battery messages and they were all different, so when she clicked on one and it went away, there was another there that made it look like it was telling her again.
Computers are annoying.