Jakebrake

I have a 2002 Pathfinder with 3.5 L V-6 that cranks well but does not want to start. I checked the obvious things like fuses and relays and I could find nothing that looked open or burnt. Can't hear the fuel pump running when key is switched on(don't know if I ever could) so a relay or fuel pump may be at fault. It is a Le model and has a security feature (not sure if it has an immobilizer) that might be causing a problem...Kid lost the key and we had a new key made...don't know if that caused the problem, the Kid said that he first had the problem with the new key after it was made but it eventually did start. Anyone have any ideas? T his vehicle is new to us and I'm not that familiar with it. Thanks for any help.