The laptop turns off a minute after turning it on, what could be the problem?

Question

Iron

Patient: Toshiba Satellite L850 D1B
It happened like this: I was sitting at my laptop, working, at some point the cooler whistled and, as I understood later, stopped. After about 20 minutes, I began to feel warm in my legs (the laptop was lying on my feet), and after touching the bottom I realized that the laptop was very hot, looking at the temperatures in the Speccy (they were at 90 ° C there), I noticed that the cooler was not spinning and immediately turned off the laptop.
First of all, I took it apart, cleaned it, noticed that the cooler was spinning hard, fixed it, changed the thermal paste right away, put everything back together and ... nothing.
The laptop turns on, the indicators are on, after 30 seconds the cooler turns on (it's strange why), there is no picture, that is, the screen does not turn on at all, and after 30 seconds the laptop turns off.
Tried to run with one memory bar changing slots, tried with one disk, with and without a battery, etc., none of this helps.
Inside: the processor is heated, the video chip is heated, the bridges are heated, the RAM is also, the hard works.
Tell me what could be the problem.

Answer 1

"Uncle, I know what's broken with you"
Well, on the topic - an overheated percent like an overheated engine will no longer be the same. Options "why does not plow" CAR. From the banal overheated bridge, to burnt tracks on the mother or swelling of the conduits. Choose to taste.

Answer 2

Turn it on, open the bios and watch the temperature. Perhaps due to heating to critical and turns off. The cooler is not cooling.
30 seconds should be enough to get to the bios.
Is the cooler installed correctly? Is the thermal paste doing its job?