6 Indium

Alienware X51 - not powering on, just the dim white light stays on

Okay, so I was playing FIFA 16 yesterday and the system must have been on for 4-5 hours when this happened. The system turned off itself and been trying to turn it back on since then, but to no avail. The Power Supply Brick is obviously working with the green light on.

I have already tried draining the charge (didn't help). Plus my system is out of warranty so I need to assure myself first as to what exactly is the problem rather than paying 1000 bucks for a technician from Dell visit my home. 

Is there anyway I can check if there is a problem with the "power button"? I obviously want to begin from there prior to proceeding on major components like motherboard. F.Y.I. I am from India and when I called the technical support, it took me around 15 minutes to explain to the technician that I am having a Desktop PC with an external power supply. He kept thinking that I was talking about a laptop despite me being very articulate of the facts. This too in a way helped make up my mind not to trust the "TECHNICIANS" here and rather figure out the problem myself and to consult them as a last resort in case I need a replacement done.

P.S. was very happy with the performance of my X51 till now. Really need to get my machine up and working again. Please help!