I have a Presario 700 which went dead screen on us. The LED's come on and I can hear the fan and harddrive running. I connected an external monitor and still nothing. I did the full power down with no battery or AC and held the power button 15 seconds, zip. I unseated the memory and powered down again, nada. I disassembled the machine and reseated the processor, still nothing. Any help? What next, a new Motherboard? It was replaced once already for unrelated problems. VERY frustrating.