Once power on my PC suddenly off and try to on time and off

I checked my psu work well. As per service centre all hardware working good. They didn't check my ssd

@shaarimajs

How long is it on for before it turns off and then turns on again e.g. does it boot into Windows or not?

If it does how long is it in Windows before it resets?

If it doesn't boot into Windows can you get into BIOS on startup and check if it stays on when you are there?

If I give long rest like long week without trying to on it, it boot windows and work approx 1/2 hr. After immediate try if got shutdown PC will not boot to window. It will be like in that video link.

@shaarimajs

Try creating a bare bones PC and check if it starts OK so that you can get into BIOS with a display and that it stays on.

Disconnect everything from the motherboard so that all you have is the CPU +CPU fan, ram, PSU, mouse keyboard and monitor connected.

Disconnect/remove everything else e.g. GPU card, SSDs, RGB lights (if any), case fans etc etc.

Just trying to eliminate if it is power related or if it is something else.

You have to start somewhere, especially if it is intermittent

I try that one also by remove the Motherboard from case and connect everything except ssd. Can't get display without gpu since my CPU is 11400F (not come with inbuilt gpu)