Very bad issues

I help my friend build a computer about two months ago and it has been working fine up until 2 days ago. He was in a game of Dota 2 and it randomly restarted so he thought it was a onetime thing, but it got worse the restarts started happening everytime he got logged on to windows and now it says no signal on the monitor and the mouse and keyboard doesn't work. The disk tray still opens and the motherboard still has and LED light that lights up and the power button on the case lights up. He put it in safe mode and it didn't crash but now he can't get to safemode. He also tryed unplugging everything from the back of the motherboard and the front of the case and restarting and it didn't work. He ran CHKDSK before it restarted everytime he logged into windows and it said scanning and repairing but that didn't work. Sorry if this is in the wrong forum topic. He has removed the ram and put them in one at a time to see if it was the ram but that didn't work. Any help is greatly appreciated.

His specs are:


My best bets would be ether motherboard drivers, gpu/gpu drivers, PSU (corsair cx series is well known to use low quality components)

Try installing windows again (hope you have partitioned the HDD so you won't need to format the whole disk) and newest drivers from manufacturers website and see if it helps

Has there been any BSOD? If so, what is the error?