Computer shuts down randomly

[NotAGeek]

A friend of mines computer suddenly turned off after leaving it on overnight, we thought it was stuck in deep sleep, but that wasn't the case. we cleared CMOS and tried to wake it up but didn't end up working, the motherboard lights where on so surely that's working properly(so i think)
we assumed he had a power surge/outage and bought a new power supply and a surge protector (since that happened to his brother twice, unlucky bastard), it ended up turning on his computer but it started to randomly shut down every 10 - 20 min.
we know the problem cant be the CPU overheating since we check the temps and they seem fine and we where just looking at the desktop in windows 10 and browser NO Games running

we tried to see what could be causing the problems so he checked all the wires and everything seemed fine, we changed ram to a different slot( he forgot to properly push it down and he didn't get a display until he notice that he didn't push it all the way down, ram seemed to work still since it was using 2.4gb; checking the task manager) that didn't fix the random shut down.
We ran a quick virus scan, nothing came up.
we can't seem to find the problem, unless his Motherboard is the problem...
 

Any thoughts anyone? would appreciate some insight.
CPU: Ryzen 1700
Ram: 8gb
GPU: EVGA GeForce GTX 1070

Motherboard: ASUS PRIME B350-PLUS AM4 AMD B350

Power supply: EVGA 600w

SSD:kingston 120gb
HDD:500gb

[ACEHACK]

maybe a ram incompatibility or some bios setting messing everything up try to use microsoft sysinternals notmyfault.exe and look at the dump files 

[rheyL]

new PSU? then mobo might gone faulty after receiving a power surge. 

 

try removing mobo out of the case and check all its caps. also try booting without the case. 

[NotAGeek]

12 hours ago, rheyL said:

new PSU? then mobo might gone faulty after receiving a power surge. 

 

try removing mobo out of the case and check all its caps. also try booting without the case. 

at this point i cant do that, he lives a bit far from me for me to do that.

he left the pc on overnight and it stayed on, but then i made him do a stress test on his cpu and that caused it to shutdown.
he never overclocked the cpu so i dont see how that's a problem.
highest temp was 43c which isnt a shutdown point

[rheyL]

5 hours ago, NotAGeek said:

at this point i cant do that, he lives a bit far from me for me to do that.

he left the pc on overnight and it stayed on, but then i made him do a stress test on his cpu and that caused it to shutdown.
he never overclocked the cpu so i dont see how that's a problem.
highest temp was 43c which isnt a shutdown point

let him check the motherboard for bloated capacitors or any burnt smell. 

 

[NotAGeek]

On 11/1/2017 at 9:59 PM, rheyL said:

let him check the motherboard for bloated capacitors or any burnt smell. 

 

he came over and i checked, nothing unusual besides a standoff screw stuck to his motherboard after taking it out and testing it out of the case, i removed the screw but that didn't seem to solve the problem.

in the end we stole his brothers motherboard from his dusty closet, that he thought was broken and ended up working and fixing his random shutdowns.

ty for all the help.