Here's a picture of the issue:
http://imgur.com/HdbAO

The computer becomes completely unresponsive, can't even move the mouse. I forced it to turn off and it wouldn't turn on again until after a few tries. Then it happened again less than 5 minutes of it being on. The picture is from the second time.
Anyone seen this before? Is it an issue with Ubuntu or something with the actual hardware? I never used it when it had Windows on it, so I have no idea if it happened with Windows. I've had the computer for about 6-8 months but I got it used so it's probably 3 years old or so.
I dropped it a few weeks ago so that might be related.