Why did the laptop stop playing The Witcher 3, as if it had become weaker over the years?

Question

Computers

Processor: Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz 2.59 GHz
RAM 12.0 GB (available: 11.9 GB)
64-bit operating system, x64 processor
Video card: nvidia geforce gtx 960m

Laptop is 5 years old A
couple of years ago I played The Witcher 3 without lags at medium quality.
Now I downloaded it again and hangs a lot (it's impossible to play). And this is at the lowest quality of the game.

What could be the problem?

Answer 1

1) Boot in the cooling system
2) Malfunction of the cooling system due to loss of tightness and leakage of the coolant (more precisely, air leakage into the vacuum, but not the point)
3) Old thermal paste
4) Violation of thermal conductivity in the processor itself
5) Garbage in the vent