Z790-H Bios flashback LED blinking, and pc not starting

[crtz]

Got a problem, looking for solution.

my setup:
ASUS ROG STRIX Z790-h GAMING WIFI DDR5
CPU : INTEL 13700K
RAM : G.Skill DDR5 32GB (2x16GB) 7600Mhz Trident Z5
GPU : ASUS ROG STRIX 3060ti 8GB
PSU : Raidmax Cobra RX-1200AE-B

So the proplem is:

When i shut down my pc via windows, all looking good. All turned off as usual.
But when i starting my PC via button on front pannel - it's dead, not booting at all, no sound, no coolers no led, nothing, and Bios FlashBack LED staring blinking green on back pannel. Constantly.
If i turned off PSU - Led turned off too, when i turn ON PSU - Led staring blinking again, and Power button on Front pannel still not working.

When my PC turned off, and FlashBack LED blinking, if i press RESET BIOS button, on back panel - my PC starting, and i can run bios, save and restart and its loading windows after that like usual. But when i turn of again - all repeat.

So in this case i can only start my PC with RESET BIOS button.

Since its blinking - i was thinking about update - i updated via EzFlash in bios, its now latest version. But still same problem - blinking and not running with power button.

I found small solution how to start PC. So, i turned off pc in windows. Then turn of PSU power. waiting till my MB have no power, till flashback LED stop blinking. Then i turn off PSU and Instantly press power ON button on front panel (before bios flashback led started blinking), and all starting good, as usual, all working, not crashing. Windows, games, videos, tests all working fine.

It's just started randomly. all was working fine for 1+ year, and just one morining it's just didnt started with button.

[JohnAb]

I think you've tried good ideas already and that's an odd problem. I'd try two more things:

1. Disable fast start-up in Windows (which means that powering off is like a restart as opposed to a shutdown)

2. Try a new motherboard battery

Not sure if either of those ideas will help, but maybe worth a try (and easy)...

PS One more idea - check to make sure that the BIOS flashback button has not become pressed in and stuck. It could be caught on the motherboard shield if not positioned correctly.