|I recommend you bench test the board before replacing any parts. |
With the motherboard outside the case connect ONLY the following: Power supply, CPU/w HS/fan, 1 stick of RAM, graphics card/chip, monitor, keyboard. NO additional hardware and no case to board wiring. Start the system by momentarily shorting the two power pins with a screwdriver. Ram should be in the #1 slot.
While the board is out of the case, verify you have not installed standoffs where they don't belong and have them under every screw hole. Board should POST to hard drive error.
If no beep at start up remove the RAM and see if beep error is heard.
I suggest you clear the CMOS before performing this procedure.