Wont power on and all lights stay on when inserting battery

I misplaced the charger for my Nikon Coolpix S220 over a period of a couple of months. When I finally found it again and charged my battery overnight, I found that the camera would no longer power on. When I insert the battery, all of the lights on the camera stay lit. Pressing the power button does no good. I tested the battery in a friend's S220 and it is in good working condition. Any ideas on what could be wrong with the camera? It was in good working condition before this most recent battery charge.