ASUS X550JK Random Shutdowns

[AsheraTR]

My laptop shuts down randomly. Mostly when playing games or sometimes doing nothing. I did a stress test to CPU and GPU benchmark. Sometimes it shuts down, sometimes it doesn't. I tried Windows 7, 8.1, 10 but the problem still exists. What can I do?
Edit: Model is X550JK-XO012D

 

[velo3100]

It is most likely a heat issue. If it is in warranty, I would sent it back. If it is not then you can try cleaning the fans and put new thermal paste. Otherwise you can use a compressed can to clear dust. Also you can use a laptop cooler.

 

[AsheraTR]

I cleaned the fans but I think that's not a heat issue. Because sometimes it just shuts down when the temperatures are 40-50. And I did a CPU stress test and GPU benchmark at extreme/ultra graphics but my computer didn't shut down.

 

[velo3100]

Have you used hdd tune to check your hdd or use memtest to test the memory?