Why won't it boot suddenly?

I could not find my exact model. It is X756UB, I think.

Was running a live version of LXLE (Ubuntu based) from a flashdrive and had it connected via HDMI to a TV but forgot to plug in the power. While watching YouTube the audio suddenly started to loop and then stop at a frozen frame. So I shut it down with the button but now it won't start.

Ive tried for MINUTES and I'm all out of ideas.

This already happened a couple of times since I got the thing. Sometimes takes seconds, minutes or even hours to suddenly work again. How can I fix this?