It's a HP ProBook with Windows 7, about a year and a half old. It's recently started randomly shutting down when not plugged in. I've checked my power settings; they aren't doing it. I've heard overheating suggested, but how would it e overheating when it only shuts down when not plugged in? Could it be a battery problem?
And no, it is not hibernating or going into sleep. It is completely forcing a shutdown.