PC I built for my friend crashes for seemingly no reason

eren_jaegerbomb

Prominent
Dec 6, 2017
3
0
510
So I built a PC for my friend. It ran perfectly fine for about 24 hours, but he got a new monitor and downloaded a game called snow on steam. the next day as he was playing the PC crashed and turned back on like normal. So then i had him try to download fortnight to see if it was just snow, PC crashed again then sent him into a boot loop. PC wont stay on long enough to re install windows.

Specs for the PC are as follows:
Ryzen 5 1600
MSI x370 gaming plus MoBo
G.skill flare X 16gb 2400 kit
MSI DUKE GTX 1070ti
EVGA G3 evo 650 watt PSU
DeepCool captain 240 mm AIO cooler

I think its the PSU maybe being defective or maybe the ram? But im not sure and would really appreciate any help i can receive. Thank you so much for your time and answers!
 

eren_jaegerbomb

Prominent
Dec 6, 2017
3
0
510

No blue screen, it shut down almost like when you push an overclock too far. Just black screen right into reboot. There is no overclock in place on the machine. Also its windows 10 pro 64bit
 

eren_jaegerbomb

Prominent
Dec 6, 2017
3
0
510
I Had him check temps while it was on and nothing was spiking