PC restart while playing

Hello. I have a big problem. After a few minutes of play, the PC reboots. This happens, however, only a few titles. These are the ones that I've had this problem until now: LOL (immediately or after 15/20 minuts), Guild Wars 2 (after about 15-20 minuts), Dead Island, The Witcher 1 (a few seconds, a minute maximum), Defiance. The problem is always resolved by lowering the graphics to minimum settings and with this configuration i can't accept it. I searched far and wide solution to this problem some time ago, but nothing worked, so I feel obliged to ask for help here because it became something annoying and unbearable for me. The characteristics of my PC are these: Intel Core i7 5820K @ 3.30GHz MSI X99S MPOWER Nvidia GeForce GTX 980 Inno3D Samsung SSD 850 PRO 256GB Western Digital Caviar Blue 1 TB G.Skill Ripjaws 16GB DDR4-2666Mhz Enermax Revolution 87+ 850w gold With "Defiance" it restarts only when the screen displays the effect present in this video at 17:41 https://www.youtube.com/watch?v=-_C_Uc0fXRE SORRY FOR MY ENGLISH :(
Report as:
Offensive Spam Harassment Incorrect Board