This applied to one of our regular business customers who had brought in a Samsung laptop with a bad habit of shutting down unexpectedly, usually in the middle of working on orders when it matters most.
A quick visual inspection reveals the cooling vent from the main processor and graphics chip looks to be blocked up and you could feel the excessive heat build up after only a couple of minutes, this would cause the laptop to shutdown to prevent damage to the processors core.
Here you can see the extent of the dust build up obstructing the vents.
Once cleaned and reinstalled the laptop will perform its workload in the manner intended and no more unexpected shut downs and lost work.
We do see this quite often as people rest the laptop on carpets or beds and the cooling fans suck in the fibres which build up and eventually block up the outlet vents resulting in slow systems and finally shutting down as this one did.