OK,

I understand it a bit better now, when you take the case off you do not remove the front...............don't worry there won't be another button.

Now, let's try this:

Push the power button in and HOLD IT IN like for a few minutes. With any luck you should see some of the other lights.

If by some stroke of luck it starts to boot, let it (keep the button pressed in all the time) then <start> and <shutdown> with your mouse. Then let go of the button.

These switches a spring loaded and the little clasp that holds them in the on position sometimes breaks or wears down.