make sure the fans in the computer are working. you might need to buy a think that you set your laptop on that cools it off (my bro has one for his dell) you should also download a temperature gauge/fan altering program. it will tell you what your computers temperature is and will let you control your fans, so you can turn them up if you need to. if all that doesnt work, you might just wanna try slowing down your processors clock speed
you can open your case, and spray it with dust off or what every, and for a fan, I don't know if you can install an extra one or a cooling system. I have limited knowledge on laptops. I have only worked with pc's.
I had a problem with that on mine...when i lifted it up a certain way it powered off. Turned out that was a loose connection that when the laptop was flexed like that it pulled that cable out.