Why did my laptop turn off by itself?

The phenomenon occurred quite often today, watch the video, then I wanted to start it up again, a short time later the screen was already black again, now I was just 2 minutes online, again black screen. What's wrong with my Lappi? Is that over now? What does that indicate?

It may be that the temperature is getting too high because the fan is not working properly anymore:-)

Check with a tool the utilization of the components and their temperature.

The laptop is cold, if it were overheated, would not it remember the case?

Not necessarily, that must be a program for reading!