Question Everything not plugged directly into motherboard randomly turns off

[YDYT]

On a reasonably regular basis, everything that is not plugged directly into the motherboard will turn off, meaning monitors, all USB devices that are plugged into my front ports, even the power light on the case turns off. However, the lights on my GPU, ram, CPU cooler all stay on, and the fans keep running. The power button no longer works, so I have to turn it off at the back on the power supply, and then after turning it back on, it will remain in this state if I power it on again. I usually have to spend about an hour messing with it, by unplugging power supply cables, and making sure everything is properly plugged in, before it starts to work again.
I took it to a computer repair store, and it happened to them and they couldn't figure it out, but it stopped for a few months between then and now, and yet it has started again.
I have no idea what to do.


CPU: AMD Ryzen 7 1800x
Motherboard: MSI B350 Tomahawk
Ram: 32 GB Ram
SSD/HDD: Samsung SSD 960 EVO 250GB, Samsung SSD 850 EVO 1TB, ST3000DM008-2DM166 HDD
GPU: NVIDIA GeForce GTX 1080 Ti
PSU: Corsair 750X
Chassis: NZXT H440
OS: Windows 10

 

[Lutfij]

When posting a thread of troubleshooting nature, it's customary to include your full system's specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

I would ask you to take a look at other wall outlets in your crib and see if the system behaves any differently on said outlets.

 

[YDYT]

When posting a thread of troubleshooting nature, it's customary to include your full system's specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

I would ask you to take a look at other wall outlets in your crib and see if the system behaves any differently on said outlets.

Thank you, I have updated the post with this information. I've tried it on other plugs and the same thing has occurred.