1. Clearly you should try turning it on and off several hundred times. You want to be absolutely sure it is dead and not just taking a rest. Once you confirm that it is 100% not going to work you can proceed to step two.
2. Taking the camera in your preferred hand, walk with it into the kitchen/bathroom/bar - basically anywhere you have a counter or hard tile floor. Now, you have to be very precise about this process. Carefully lift the offending camera in your hand and bash it full force on the counter/floor repeatedly. It helps if you use your angry voice and yell 'Why aren't you working you piece of s**t?! Why! Why! Why!'
Once you've done this, try turning it back on. You may be presently surprised to find that it now works perfectly fine. I know mine did...