After being driven and ran sluggish and died several times?

It started after being driven and ran sluggish and died several times. I got it towed home and when listening for the fuel pump to prime, it wasn't. We replaced the fuel filter first, which was very, very dirty, then replaced the fuel pump. You can hear the fuel pump priming but the car still won't start/run. We did check for spark and it does have spark, when you turn the key, you can hear the fuel priming at the injector rail too, but still won't start. I'm hoping you could give me some idea what could be causing this or where to look next to get the car running.