IIRC all the lights on the board are under software control. That makes it hard to tell the difference between a bad software image and a fried board.
However if you have tried SD card recovery and nothing happens (both Android and Debian SD card recovery images should start blinking LEDs about six seconds after power on) then its likely there is a hardware fault of some sort.
You mentioned applying power to the GPIO, which worries me slightly. What do you mean here?