Will not! It boot eliminated the power supply and main board...

I eliminated the complex items by replacing the main board with one I got on eBay that was fully tested and warranted, to be 100% sure that was not the issue. I was told the original board did not have capacitor issues by my local Apple Genius Bar. Secondly, I eliminated the power supply as being an issue due to what the diagnostic LEDs were telling me. Number 1 LED lights up when the AC adapter is connected to both the computer and a wall outlet. I'm beginning to believe it is something ridiculously simple. Any opinions? If u need further info, please let me know. Thanks in advance for your input!!