Question PC stars up only if I previously cut off all power to it...

[marko.master371]

Ok, so just today me and my brother received our new motherboards, new Ryzen 5 3600 CPUs, new PSUs, etc. We plugged everything in, after a couple of hours we had our PCs completely set up and running, we were thrilled. But then the problem came, after we concluded that our PCs are working we decided to have a lunch break and so we shut down our PCs. After around 30 minutes were arrived, pressed the power button, each at our own PC, fans start spinning, but then nothing, no display... I decide to try to shut mine off by holding the power button, it didnt help, so I had to press the power supply switch to shut it down. I tried turning it on again, but the same thing happened. My brother, after he turned off his PC, decided to try out to unplug the cable that had all his PC components connected to it, including the monitor, and after trying to start it up again it launched with no problems at all, I decided to try the same and it worked. After turning off the PC again it happened again, then I unplugged the cable, plugged it back into the wall and voila, it worked. My brother's PC fell asleep while we were trying to figure out the solution on mine, and he was unable to wake it up, only solution was, well... to plug it out of the wall, so not even putting my PC to sleep would be of any help. Here are some notes:
We didn't order the same PSUs, since the store didnt have any that are the same in stock. Both PSUs are 600W.
The motherboards are both B450M DS3H from Gygabyte. Both CPUs are Ryzen 5 3600 with stock "Stealth Wraight" coolers. We don't even have the same RAM, he kept the RAM from his previous PC, but since I had DDR3 I had to order new RAM. We both have GTX 1060 GPUs.
Also, if not perfectly clear, all the stuff we got was brand new from the store, it wasnt any second hand shop or anything, but practically the main supplier of PC parts in our country.
So at the end, is there any solution to this, I don't want to have to unplug my cable out of the wall (it is under the desk) every time I want to turn my PC on

 

[Archaic59]

If you only plug one system into the wall does it run ok? If so, you may be overloading the circuit with 2 computers. This generally isn't an issue in the US but depending on where you live it's a possibility. Also, make sure you're not plugged in to an outlet controlled by a light switch and especially not an outlet controlled by a dimmer switch. Even if the 2 systems are powered by different outlets they could both be on the same circuit if they're in the same room. Just taking a guess here.

 

[marko.master371]

Nope, we unplugged one PC but the other one wont turn on. The strangest thing about everything is that the PCs wont start up if the psu has been unplugged, but literally all power must be completely cut, both monitor and speakers must be unplugged as well. This is very strange