Multiple shutdown/no POST scenarios

[stevemont7]

Hello, over the past few months since building my PC, I’ve had four instances in which the system powers off suddenly and will not power on again. The shutdowns have occurred at idle, while playing a game, and while restarting. 
 

There are no loose power supply cables, and clearing CMOS does nothing. However, if I disassemble my PC and breadboard it, everything turns on and runs fine. This led me to suspect a short, so each time I would reseat the standoffs and motherboard, but then the problem happens again eventually. Any suggestions would be greatly appreciated. 
 

Specs:

Windows 10 Home 64-bit

MSI MPG Z490 Gaming Carbon WiFi (BIOS version 7C73v14)

Intel Core i7-10700K (stock speed)

2x16 GB Ballistix 3200 MHz

Nvidia RTX 3080 Founders Edition

Crucial P2 1 TB M.2 SSD

Corsair RM750X

 

[lafrente]

check IO plate seated correctly

[Kavamale21]

try to get UPS for your pc depending on region and time of day some you can get quite nasty experence running strait from socket. in flat i live in uk had to change 3 motherboards before got UPS.

[stevemont7]

9 hours ago, Kavamale21 said:

try to get UPS for your pc depending on region and time of day some you can get quite nasty experence running strait from socket. in flat i live in uk had to change 3 motherboards before got UPS.

Thank you for your response. I’ve actually encountered this issue when I had my PC plugged into a normal surge protector and when plugged into a UPS (like it is currently). 

[Kavamale21]

8 hours ago, stevemont7 said:

Thank you for your response. I’ve actually encountered this issue when I had my PC plugged into a normal surge protector and when plugged into a UPS (like it is currently). 

so pluging too UPS fixed or you still have problems?

[stevemont7]

I’m still having the same problem when plugged into the UPS. 

[stevemont7]

On 2/14/2021 at 3:58 AM, lafrente said:

check IO plate seated correctly

I think we might be onto something here. This problem happened again, and just kind of pressing on the IO plate with my fingers got my PC to turn on again. Problem is, it’s a preinstalled IO shield—is there a way to adjust that really?