How can I stop my computer from overheating?

"You can open your laptop and clean the dust out of it. Also you can reapply the thermal paste to the cpu. Make sure you clean your old paste off. Use a coffee filter to clean it off. That should make it run a little cooler.

How to Apply Thermal Paste"

First, try moving your computer to a flat surface to make sure the ventilation is not blocked. If that does not work, you should clean the internal fan, this will require some disassembly. The last thing you could try is replacing the heatsink thermal paste.