Critical Error Event 41:Kernel -Power

Hi Everyone ,
I'm facing problem in win 7 professional while working ,my system has crashed randomly. and when i chk in event logs there are 2 critical error showing below message:
The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.

i'hv already formatted this system twice but it's happening again , i have run all memory test , graphic, overclocking , psu test but haven't got any error.
i don't know why it's happening with this system only.
Plz help me as soon as possible.

Ok you have a hardware problem. Start replacing parts. If you are overclocking slow the system down until you don't get these reboots. Better to set it to the standard/Default speed and test. If no reboots then bump it up a little and test.

If you still get the reboots with the system at its default speed then there is some piece of hardware that is causing it. More then likely RAM.

In your SF specs it shows Dell Vostro V131.
From what I found it looks like this a laptop, right?
How old is it, and is it still under warranty?
Maybe it's overheating - have you checked temperatures?