Check for physical reasons, is the button stuck, way loose, or visibly broken? Is the lid cover button stuck? you know that little switch that can tell when the screen is closed. did you drop it or something? Any loose parts rattling around when you shake it? was it plugged in durring a power outage/ electrical storm? did you smell anything weird from it like burning rubber?
Is there a factory reset button? how about holding down the power button for a good while?
The power button isnt stuck it looks like it works, the lid cover is fine, i dropped it a couple times but it worked fine after and that was a while ago, no loose parts, i think it may have been plugged in during a power outage, no weird smells, im not sure if there is a factoring reset button i looked every where without unscrewing anything, and yes i tryed holding down the power button