Laptop eh.

Monitor your temps, see if there is any spike while doing things. If you are unsure of any temperature monitoring programs I suggest "Speccy". Get a solid average read of when your computer is idle, then start up GF and heavily monitor your temperature. Not just alt tab every few seconds, stare at it until your system shuts down. You're looking for spikes in your temp and any sort of high temp before crash.

It sounds like one of three things.
A: Your CPU or GPU is overheating to the point where your laptop is auto-shutting itself off to prevent hardware damage. These things can be pretty easy to fix. Adding a fan near the outside of your laptop is not a fix.

B: Your computers power box/connector is wonky. I'm not really leaning towards this.

C: Your hard drive is shot. This would probably cause more problems then just shutting off because I've had this problem personally with a laptop of mine. You would be getting a orange~ish blinking light hard drive light on 90% of your start ups, your computer won't start, etc etc. But, just putting it out there.

If anything you should get your computer checked out by a tech if you're not really good with tearing apart your computer and checking things like your thermal paste, if everything is seated fine, if there is a lose wire etc. because you'll take the chance of voiding your warranty on parts which won't be worth it if you have no idea what you're doing.

But definitely try to get a temp reading before your computer shuts down while GF is up on both your CPU and GPU. If you're unsure about "safe" temps or if the temp it's reading is too high, just post your idle temp and then the spiked temp you had before it shut down here.