Why my cousin's gaming laptop keep crashing while playing or opening any games,also with steam games??

Acer predator helios neo16, i7- 14700HX, rtx4050 6gb gddr6 vram, 16gb ram, 1tb ssd.. why it keeps on crashing while opening or playing any games, sometimes it works fine then suddenly crashes also steam games keep crashing.. he has cleaned his laptop recently and he also replaced his thermal paste and installed his windows again .. is it due to his ssd,ram or due to his graphic card or some circuit is short.ps his gaming laptop has been 3years old btw..