remove all add in cards, hard drive, etc. run the system with only CPU and 1 stick of memory.
try to flash the bios, again.
Also try using a PS/2 keyboard and see if F7 works.
unplug any usb keyboards/mouse/etc.
Thank you very much for answering. I flashed the bios with only video card present on the board. Unfortunatelly, the system is not passing even the beging of POST sequence... When system powers on, it gives three beeps pause and the sequence repeats continuously with 14 indicated on the POST indicator. This happens whatever mode I choose: normal, maintenance, recovery. Also, nothing is displayed on the monitor at all.
Did you try with only one stick of memory?
I've had problems getting this MB to boot with all four memory slots filled. I would get the three beep memory error and the ONLY way I could get the computer to boot was to remove at least one stick of memory from the fourth slot from the processor.
I now have it working but cannot set the memory to 1600 as it should be or it will give the beeps.
EDIT - I just updated my bios from 083 to 085 and no problems so far