DH87MC

I have an intel board DH87MC when i turn iton it doesn't boot from first attempt.

When i try again i got : "BIOS has detected unsuccessful POST attempt(s)... Press "Y" to enter Setup or "N" to cancel and attempt to boot with previous settings.". When i press N the pc restart and works normally.

I tested many Hard disks , power supplies , and rams same problem.

Please help me.

Thanks

Attached you can find the error..