So I'm servicing a Macbook with a flashing question mark folder and all the usual stuff (hold this button, hold that button) is not working and I can't even start up in target. In fact, the keyboard shows no signs of life at all. (don't tell me it died the same time as the HD!) I got no caps lock or num lock light. The only button that seems to work is the power button. I plugged an Apple USB keyboard/mouse and still couldn't get anything. I swapped the ram. I even pulled the HD and stuck it in a MacBook Pro and it's fine. when you press the power, the screen flashes bright for a millisecond then goes to about half the brightness. WHAT COULD POSSIBLY CAUSE THE FLASHING ? AND THE KEYBOARD TO SIMULTANEOUSLY GO OUT?