Well i don't really remember when it started but i've been replacing parts in my computer for quite some time. And everything worked perfect. But now when I start my games... My screen goes black but i can hear youtube playing in the background. I can't alt f4 or ctrl alt del. Its not responding. All i can do is press the reset button. And the only thing i haven't replaced in my pc is my hard drive. So i wonder if that may be the problem. Also my computer is really slow when starting up. Games that makes my computer freeze/Crash is Overwatch but only when i boot it up. League of Legends is the same. But only when it is going into the loading screen. Also sometimes when i watch youtube it suddenly becomes unresponsive and I can't click anything i can only move the cursor. The keyboard wont work and commands wont work. But if I wait it out for like 5 minutes. It kinda restarted itself too. And the commands i tried like ctrl alt del will activate like they are delayed.
GPU: MSI GTX 970
CPU: l7-4790k
PSU: Corsair CX750M
Motherboard: MSI Z97 Gaming 5
RAM: Kingston 8GB 1866MHz DDR3 CL10 DIMM HyperX Fury Black Series
HDD: St2000dm001-1ch164
OS: Windows 10
GPU: MSI GTX 970
CPU: l7-4790k
PSU: Corsair CX750M
Motherboard: MSI Z97 Gaming 5
RAM: Kingston 8GB 1866MHz DDR3 CL10 DIMM HyperX Fury Black Series
HDD: St2000dm001-1ch164
OS: Windows 10