Phone won't shut down

All of a sudden I cannot shut off my home page screen. If I quick press the end button nothing happens; I have to wait a minute for the screen to blacken on its own.

Is there a setting to change it back to the way it was before?

 

I finally figured it out. I have an application called "Spare Parts" and I had the wrong setting in "End button behavior".

This was scary because Verizon wanted me to do a complete reset of the phone which would have wiped out everything I installed. It would have cured the problem, but i would have been starting all over again - 4 weeks of work wasted.