Why doesn't my car turn on?

Recently, I was driving my car, and it was running just fine until it ran out of gas and turned off. I put gas and it still wouldn't turn on, I even tried switching the battery with a fully functioning one to see if it might have been the battery, but still wouldn't start. Also, I replaced the fuel pump and can hear the fuel pump when I try to turn the car on, but feels like no gas is going through. I also checked the fuel filter but no gunk came out so I figure its not that. Also, the car makes a small clicking noise between the filter and battery. I'm not sure if this matters but the security light doesn't turn off, it stays on the whole time. When I step on the gas pedal it feels hard, and there seems to be a hose that is disconnected from somewhere not sure were it goes, but its right next to the engine.