try removing the cmos battery for 15 mins.......try the motherboard out of the case,with just the cpu with fan,memory, make sure the motherboard has an on board buzzer to here any beeps.....if the ram is faulty you will not see anything on the screen, the same for the cpu...but the majority of boards will still beep an error code if one of these are damaged....so most likely is the board at fault...but try the above first.
regards
danzil