Question Random power failure

Aug 15, 2020
Hi, My pc have come across a weird problem of random power failures and i've been trying to solve it since a long time.
the problem started with occasional power off and restarts but happened only once or twice the initial week.Then the
frequency of the problem increased and started to happen every day,then multiple times per day like between couple of hours.
But whenever i kept pc from not using for some days the issue solves for 1 or 2 days then again it happens slowly as mentioned.
Its like the more i kept pc not using it works fine the more time.Then power failure is not happening while doing a particular task
like gaming or editing.the temperature is also normal,It happens so randomly,i even gave it a stress test and seems fine there.
The problem happens even in the bios screen,so it might not be a os issue.I also checked/replaced components like SMPS,CPU FAN,RAM.
The problem is clearly a motherboard issue.So anybody here has any solutions other than replacing or any guess which part of the
motherboard has the issue?

please help!!! please help!!! please help!!!