Alienware 18 keyboards blinking no screen, and not beeping?

Hi I have a Alienware 18 keyboards blinking no screen?

I tried taking the ram out and it beeps no ram, also beeps CPU but nothing in between.

Does anyone know what that means,  I've worked out that the Lcd is faulty so have replaced, have tested CPU,  ram and video cards.

 Anyone know what this means,  I think the motherboard might be dead?