Instructions
Press the power button on the Xbox to turn it on. Some consoles will come right back on even after a shortage in power.
Unplug all the cords from the back of the Xbox console if Step 1 did not work. Also unplug the AC adapter from the wall.
Plug the AC adapter back into the Xbox along with the other cords. Turn the Xbox back on and see if the console powers up.
Buy a new AC adapter if the Xbox still will not power up. Adapters for the Xbox can be bought at most electronic stores.
Unplug the old AC adapter and plug in the new one. First plug the wall end of the adapter in and make sure the green light on the adapter box turns on. Now plug the other end into your Xbox and turn it on. Your system short should now be fixed.