OKay, So I got my Lumia 920 today.. I let is totally discharge today once so that I can start charging from 0 to 100 once. Its been almost 2 hours now and the phone has still not started again....
I would never recommend killing the battery and then doing a full recharge.. I would suggest you try performing a soft reset (Volume Down + Power Button) for about 5-8 seconds until you feel a vibration and then wait for the phone to boot. Also if this doesn't help charge the phone for about 2 hours then perform a hard reset( Nokia Lumia 920 hard reset - PDA Smartphone PNA hard reset soft reset) until you revive it. NOTE: do not try a hard reset with no charge on your battery.. The hard reset process should take somewhere between 10-20 mins so make sure you got enough juice in the battery. If these still dont wake up the lumia then replace it.
Try this volume down and power reset couple of times it should revive the phone. cheers.