The P's is just an error I believe which requires you to replace the entire guage cluster... but I'm not sure.
The reason it's not starting is becuase the gas is bad and probably filled with water. I dont know any easy way to get rid of water in the lines except to drain the tank thats in there by disconnecting the fuel injectors, and running the fuel pump and injectors by connecting both to a 12v source... you might want to have a mechanic or dealer do this...