My Toshiba L770 Satellite Laptop does not power up, no LEDs lit when power adapter is plugged in. Power adapter producing 19.4 volts. Opened up laptop and got 19.4 volts at end of power connector harness when not connected to motherboard and approx 0.5 volts at connector pins on motherboard when adapter is connected. Visual inspection of motherboard showed no obvious problems. Battery doesn't have any affect, whether installed or removed. Also removed BIOS battery for 30 seconds and reinstalled. Still no sign of life from laptop. Does this sound like a bad motherboard?