POST SCREEN FREEZES

i have a friends computer to repair and when i turn the computer on it stick at the motherboard logo screen. i am unable to use the keyboard,nothing happens..it just stick there.
i have resseted the bios, unplugged everything and just leaves the memory and motherboard along with the video card running. still get the same thing.
computer is used for gaming. he told me he didnt over clock v/d card nor the motherboard. i believe he tried to over clock the motherboard FSB and get this.
CAN ANYONE HELP ANY SUGGESTION.

i also changed the video card already and i get the samething, sometimes i switch keyboard from usb to ps2 and get no response..sometimes i c nothing on the screen.