Motherboard behaving strange

So my pc stopped working some days ago, pressing power button or sorting the board pins do nothing now, I've faced this same problem last year as well, where it will work normally at the computer shop but wouldn't start at home.
I did lots of digging on this issue last time and found out it was the motherboard, it was under the warranty so i took it to the service centre and shared my issue with them and got the board in about a week, but it was same no response when sorted the pins, but worked at the repair shop... So i took the chance and changed the board, which worked.

Now I'm facing the same issue, i took this board to the service centre and it just worked, so i told them about the problem and what happened last time as well and asked them to replace it if possible. They replaced my board and showed me that it was also working, however it didn't start at home (didnt put it in the cabinet). I went to the service centre again this time i brought process ram and psu as well and it worked just like that.. i still insisted to check the board thoroughly, to which they agreed.
I dont understand how is that possible, what is this problem. If anyone has anything on this please share it'll be a great help.

veeg said:

Hello

What was the complete spec's of the old psu? Also the older spec's of the ram.

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Computer specs :
Ryzen 5 2600
Amd rx 570
32 gb ddr4 3200mhz ram (4 sticks)
Asus x570-p motherboard
Antec 550w white plus psu (old)
Evga 750w golu plus psu (new)

veeg said:

I would say that old antec psu was the main issue.. It's just cheap.

The ram upgrade helped as well.

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Yes you have a point but what i dont understand is that why would it just start normally at the shop, even with only processor and ram connected it starts just fine the shop and the service centre but doesnt start at home.

veeg said:

It is weird i know. I see this all the time on these types of forums.. Another thing check your power outlet at home, you could test another outlet to see what happens..

Edit: That particular outlet.. how many other devices are running off of that one circuit?

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Yeah I've tested other outlets and i dont understand what you mean by one circuit

veeg said:

Ok here in the U S we have electric lines that are separated by breakers or fuses, each electrical line can be called this or the electrical circuit. These independent electrical lines spread out the electrical feed thru out the home.. When the one circuit is over loaded with other devices plugged in , the power supply drain on an another can effect how it runs/performs. Also if the electrical outlet where you plug in your pc may need replacing because of poor contact to the electrical cord that runs your pc. Since you have tested that and still have an issue, it may have come down to that antec psu anyway.

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Yeah that, I've tested on different outlets at different rooms and results were same.
I've replaced the antec psu to evga 750w psu, still nothing changed.