When I power on the machine. From time to time the motherboard get stuck on blanc screen before bio splash screen and AsRock - logo.

Reboot, unplugging power cord for long time (hours) has no effect. It just stays stuck in the blanc screen at boot.

When this happens the fans spin up really fast for a second then then spin down. Even if the machine is room temperature from being un-powered for more than 12 hours, so it can not be overheat. Machine is still responsive, it seems to respond to keyboard. Some magic combination of hitting the F - keys and enter does get it to reboot And some time ctrl+alt+delete reboots the machine. This gets it out of the freeze state. While power button (unplugging power cable for hours) does not help, it just gets stuck same way on power up.

It seems like it is in some error state, liek displaying "Press F1 to enter bios, F2 to load defaults" etc. - but monitor is blanc - no signal and after navigating this invisible dialogue the machine reboots and then boots ok.

It has 600W Silverstone SFX PSU (I know that is minumun requirement, but tested on 750W ATX PSU and froze on that too)

16GB corsair vengeage DRAM

There is not OC or anything, I turned off some features that I do not need to lower power consumtion, like front panel audio.

On boot the machine freezes on permanent black screen on boot, any reboot then and it does advance from that blank screen, even switching PSU etc does not get it out of that freeze. This happens like on every 10th power on and once it happens consequent power ons do not get past this state.

Has anyone had this happend to them ?