Anyone who knows something about laptops?

My Samsung laptop, now about 5 years old, is having issues. It keeps shutting down on me.
I don't know what the problem is, but when I do too much at the same time, it just shuts down, like it hasn't got enough power to keep doing what it's supposed to lol.

Could it be a power thing or could it be the fan overheating? I don't know...but hope I can get it fixed.