Hi. I just installed new FM2A75 Pro4 motherboard and I have following problem. When you reboot you PC from Windows or BIOS it won't boot. Screen is blank and you see "7C" on motherboard's LED indicators. You can boot it only by pressing hardware reboot button or by turning it off and on again.
Nothing is connected to the MB, only HDD, video is internal.
Model is this one: http://www.asrock.com/mb/AMD/FM2A75%20Pro4/CPU is AMD X8 5600K.
BIOS is latest, made no change.
What can be the problem? Is there a chance to fix it without replacing the motherboard?