sudden strange problem

[Griff7520]

Hi

Have a problem starting the pc. Its been running great but this morning I pressed start on case as usual but the pc would not boot. It did for a few seconds there was power there but it just switched off again.I had to press start several times before it actually started and once up and running its fine. Done loads of tests ie ram cpu etc etc but can not find a problem.

Its a new build and has been running great for 2 weeks. I unplugged everything and reseated all and still same problem. I tried different ram and still same issue.

Any ideas as to what this could be

I am thinking:-
PSU
Motherboard
case button
short some where

any help most appreciated

 

[Griff7520]

Thanks for the reply. I ended up removing the motherboard and putting a z790 board in with A 12600K which I was planning to sell and everything is back to normal. I suppose the board or chip was faulty so Have sent them back to the rain forest. Didnt know which was the faulty part so sent both to be sure. May just stick to z790 for now