I asked the dang thing to shut down. It has been "logging off" for the last 48 hours. If I press the power button and let it sit for a few minutes, and then press it again, the computer comes back on, but to the "logging off" screen! What can I do? I have tried letting the battery run out, then plugging it back in and turning it on, but it turns back on to "logging off"! HELP!