Question My PC stays switched on only for 2 seconds. Is my mobo dead?

[brvnbld]

I have a peculiar situation, that's why posting a new thread.
I have been using AMD PHENOM II X6 1075T with Asus M4A78 mobo.
I bought an used i5 4460S with Gigabyte GA B85M D3H.
The System ran fine at the computer shop I purchased.But it's not switching on in home. It just runs for a single second and switches off.
I have tried all the techniques in the sticky thread too. The PSU is fine, I checked with another PSU, another cable (power, VGA). Tried with different RAMs in different Positions.
This morning I took it to the shop and again it ran fine over there., so couldn't even say them what's the problem. please am stuck.
I also have GTX 650 Ti, but ran all the tests without it too but in vain.

Now the processor+mobo doesn't boot in the shop too.

 

[Ralston18]

If the computer works fine at the shop and not at home then I would suspect a electrical problem at home.

Have you tried the computer on other outlets/circuits in your home or at other locations?

Are you using any extension cords or circuit/power bars at home? If so, bypass them to determine if power is restored.

Then add back one by one - if power fails again then the last cord, etc. added is the problem.

Key is to narrow down the circumstances and determine some difference between home and "shop".

 

[CountMike]

What about PSU(s) ? If you have an older one with voltage switch at the back it may not be input voltage variation tolerant as newer, multi voltage ones which can typically run from 100 to 250V.