turning the ignition key but engine won't turn?

What is your question?

I stopped in to refule the explorer w/ the engine running mind you and when i got into the truck i turned the engine off to reset the fuel milage on the trip computer but wheni went to start the truck allt he lights were on but no crank it wouldn't start i have done everything made sure it was in park everything bu when i keept trying to start the truck ..like every third try the door locks would lock and unlock weard....can anyone help