Sony VAIO shuts down randomly

[Chikwa]

My Sony VAIO VPCEB1J1E Keeps shutting down at random times. Am running Ubuntu 12.04. The battery is dead, and the laptop has been running fine on AC, plugged into a socket. It doesn't even heat at all, it just shuts down randomly. If I turn it on at first, I use it for up to 2 hours before it shuts down, then, when I turn it on again, it will shut down in 5minutes. It displays a smart failure warning when starting up, so am not sure if its related.., what could be the problem?

 

[Warrgarbl]

SMART failure means that the SMART monitoring of your harddisk has determined that there are too many defective sectors to keep operating normally. Replace your harddisk, and do it soon. The sooner, the better for your data consistency.

Random freezes are often a good sign for HDD or RAM failure.