Another trick to fix the error of xbox 360 doesn't turn on, examine whether the light of power supply is at all lit or not. This denotes there is completely no power supply or no power reception. Unplug all the cables including power chord and reconnect them. You can also change the outlet if possible.

Why wont my xbox 360 turn on: No more a Deadlock

So, if your xbox 360 doesn't turn on, you can try some tricks that you have in your hands now. If nothing works, then probably the only way out left is to call the Microsoft service center.