Overheating can be caused by several things.
The first thing you need to do is figure out where the heat is coming from. No air flow means no heat transfer, so figure out where the air vents are. Are they blowing hot air, or is there barely a breeze, even when the fan is overtaxed?
Most commonly, an accumulation of dust in the vents and fans through the cooling channels will be culprit in restricting air flow. Cleaning it out will work best. Turn you laptop upside-down and look at what you’ve got.
Make sure your laptop battery is maintaining charge. Bad/Old Batteries generate a lot of heat.
I would also recommend installing CCleaner on your laptop to ensure that software isn't the cause, forcing your computer to work much harder than necessary. Scan for junk/unecessary applications and files and get rid of them.