My '02 Grand Cherokee won't start!?

I have a 2002 Jeep Grand Cherokee Laredo 4.0L with 56K miles on it.

Yesterday, I went out to go to work and the Jeep wouldn't start. Cranked once and when I turned the key again, nothing. Figured it may be the battery since I had never replaced the battery when I bought it used in March. It currently has 56K miles on it. My neighbors came out and helped me try to jump the battery. No go, but it DID crank this time. Figured the battery was just really dead and had my neighbor drive me to auto parts store to get a new battery. Put it in and it still won't start. Husband came home and checked the relays - all fine, and then disconnected the line from the external fuel filter to see if fuel was being pumped through it. Cranked the engine again and no fuel was being pumped through it. We also were not able to hear the fuel pump turn on with the key in the on position. Purchased a new fuel pump from a dealer, installed it today and it still won't start.

We didn't replace the external filter. Could this be the problem?

Is there an emergency fuel cut-off switch to the fuel pump on this vehicle?

Or is it possible that this is not fuel related at all and an ignition problem? Or maybe the Sentry key? Would my check engine light come on if this were the case? My check engine light is not on.

Car ran beautifully until yesterday. We had even driven it 120 miles each way to my parents house in Pennsylvania on Christmas Day with no problems.

Any ideas would be most appreciated.