joeisi is right, but is not without risk, worse, maybe does not solve your problem.
'cheap' laptops, even when new can hardly get rid of the heat when the cpu is running 100% for longer time.
With time, dust buildup and dried out cooling paste make it worse.
The fix, as many have said: get a laptop cooler, but check that the air intake on your is on the bottom (many new ones have the intake at the back and this does not work).
If you want to use your laptop for heavy duty: you may need to purchase a 'gaming/multimedia or workstation' type laptop, these are designed to run at 100% load.
Note: even the gaming/workstation laptops will get more hot over time.