My iPhone is dead

My iPhone was having no previous problems other than some programs that were constantly running in the background which drained the battery. The genius bar suggested that I reinstall the OS and it worked. Tonight the battery was at 60%, I put on the charger and after an hour, I tried to use it, and it's dead. I tried: 2 different cables, a wall charger, a car charger and connecting yo my MacBook Pro. Nothing worked. My Mac didn't ID it, and the car charger, with an LED light indicator, stayed green, meaning that it did not recognize my iPhone. I think this is pretty exhaustive. I purchased it last summer. And I run my business with that bugger! Is this becoming a trend? Why? Thanks for any ideas.