If your laptop is getting very hot and turning off it is more than likely that your fan and heatsink assembly is blocked.
Laptops are like hoovers and suck up dust and fluff which then gets trapped in the heatsink. Over time this builds up and eventually obstructs air flow completely preventing it from cooling the heatsink and causing the processor to overheat.
During the reconditioning of our own laptops we find over 80% of laptops over a year old have a completely or partially blocked fan. Occasionally we see laptops in unusually dusty conditions with blocked fans only 6 months after we had previously cleaned it out.
Some computer shops simply blow compressed air into the heatsink which is lazy and causes the matter to ball up and jam the fan causing an even more serious fault.
The best way to resolve the issue is to strip the laptop down and remove the heatsink and fan assembly to clean it out. The old heatsink compound can then be removed, copper surfaces & cpu cleaned and fresh compound applied giving a more efficient heat transfer
Many customers ignore their laptops running hot can eventually result in CPU, northbridge and graphics card failure. AMD Athlon processors need extra attention as they contain no overheating protection and end up cooking themselves over 100°, the motherboard may have a thermal cut out which is why the laptop my turn off. Intel processors clock down to save themselves from overheating resulting in your laptop running very slow.
Due to the amount of labour involved in correctly cleaning out a fan and heatsink we charge £50.