Laptop: Linux X200 Tablet. with Ubuntu 12.04
Some times the laptop shutsdown randomly and displays the following screens:

Did memtest. After 5 passes I see no error at all.

One of the other supposition is that it is happening due to heat. I have occasionally had the laptop shutdown within minutes after it started up.
I have feeling that it is happening because of sudden movements but when I test it does not seem to be so. I have no clue on what is happening. Please help.