Question Computer wont turn on unless i jump CMOS

[dinarior]

First - I have been thru the question from 2011 - Here, Did not find a solution.

I am using a Gigabyte GA-H170-D3H for 1151, with Intel i5-6600 3.3Ghz(3.9Ghz Turbo) Skylake LGA1151.
A couple of days ago I had to reboot my system (forcefully), was swamping the RAM and ubuntu does not handle that well.

Since then the computer won't boot up unless I jump the CMOS. Everything starts to work (lights, fans) , but the monitors stay black, keyboard and mouse some time get power, some times won't.

My motherboard always had some issues - some times getting stuck in boot screen, sometimes setting itself into fast boot for no reason.

I have tried the following:

Run with a thin setup: Only 1 stick of ram, no GPU/ peripherals/ soundcard, even removed the panel connections and booted up by jumping the pins.
Switched cmos battery.
Upgraded my BIOS.
Cleaned everything.

When I do get the computer to turn on, everything works well, did some stress test, on the GPU card and CPUS, nothing overheats, and every thing works well. So I doubt its the PSU.

Posting here before I buy a new motherboard - If any 1 has any ideas, things I could try before switching to a new board.

Thanks.

 

[Ralston18]

Just for the record:

PSU - make, model, wattage, age, condition?

Test the outputs just to be sure about the PSU.

https://www.lifewire.com/how-to-manually-test-a-power-supply-with-a-multimeter-2626158

 

[dinarior]

Using a Seasonic 600W , around ~4 years old, as the pc. for the record- Hes very healthy.

It was the mother board, got my hands on some compatible mother board and verified it. now working flawlessly with a new Gigabyte GA-H170-HD3 (no D3H was available )