Asus S551LN is totally dead. Tracing the failure?

Ok, her’s the problem. The laptop Asus S551LN doesn’t power up, completely dead. The adapter gives 19 volts as it should. Of course I have tried to remove all the connected hardware and start without any luck. I have tried holding the power button as well.

I don’t seem to find any schematics on this except some pictures of the motherboard. So I measured the continuity at the power on switch. As drawn in the image I get continuity on adjacent legs and I get continuity on opposite legs when switch is pressed. (I assume the switch is working).

There is this 3 leg mosfet (i think so) next to the powerjack. How to check if it is functioning as it should?

I couldn’t identify any power IC or diode that could be a reason for this.

Any help here?