PC always fails to boot ONLY the first time

[Tolis_GR]

Hi Toms,

Lately my computer fails to boot into Windows only the first time i hit the power or button or restart the pc. It will drive me to the bios logo screen and stay there, or it will go past to the black screen with the blinking underscore like searching for the boot drive and it's missing.
After that, if i hit the reset button it will boot normally into Windows. That happens 100% of the time. Also if i shut down the pc and the psu and discharge by holding down the power button, it will boot into Windows just fine. If i don't do and attempt to fire it up, it won't boot.
It happened in the past and i solved it by unplugging and re-plugging sata cables. This time it doesn't work.
Things i 've tried:
-Disable any OC, and load bios defaults
-Disable fast boot
-Disable all other boot drives in boot priorities and boot options
-Changed sata cable and sata port for the boot drive
Any ideas? Specs in profile

 

[schwatzz]

How old is your computer? It's possible the CMOS battery is dying.

 

[anghellic]

try removing the cmos battery unplugging the computer and discharging it then plug one in at a time

 

[Tolis_GR]

How old is your computer? It's possible the CMOS battery is dying.

If i recall right the battery shouldn't be that old. System is custom build with some old and some new parts. If the cmos battery was dying shouldn;t i see bios discarding my settings? I ll try another and see how it goes

 

[Tolis_GR]

okay, today took some more troubleshooting steps. Reflashed motherboard bios, cleared cmos, disconneted gpu and all drives to no avail. Finally i tried to boot without mouse and keyboard and boom. Booted all the way directly into Windows.
I think the problem is with possible corruption over usb controllers as i am using bclk overclock that also overclocks the bus/pcie speed. Thanks for the suggestions though