Where to start?

Lemmesee... first I would look for loose wires, vacuum hoses, bad battery cables and such. Next I would check the fuel shut-off switch and push the button to reset it (it's usually under the top edge of the carpet on the passenger side in front). Next I would check for voltage to the ignition coil and pressure test the fuel pump. If you can get it to an auto parts store have them load-test the battery.

Doesn't crank or doesn't start ??????????

Doesn't crank.

Do the lights on the dash dim when you try to crank ???

If so bad/empty battery

If not, try to start it in neutral ( bad neutral safety switch)

Still nothing , check power to starter (tap on it to loosen it)

The information seems conflicting. If the engine is not cranking then it doesn't matter, at this point, if there is a fuel problem. So let me make an assumption. All of the electrical appears to work, ie. lights, radio, etc, but when you turn to ignition, nothing. You cannot hear the starter turning the engine over. Hopefully you do not have the same problem I just had with my 95 Explorer which had just went past 250,000 miles. My son was driving the Explorer and the engine just died (and I was never clear on how exactly my son was driving it). Turns out the engine had seized up, so when attempting to start the starter motor could do nothing. The easiest way to check this is to turn the engine over by hand using a 19mm socket and breaker bar on the crank case pulley. It should turn easily. In my case I couldn't budge it. The engine needed some major work and I ended up just donating the non-working vehicle. Since this was my son's car so we decided to replace it with another Explorer, but with much less miles. We found a very nice 98 Explorer with 85000 miles for $5000. I figured if I could get 250,000 miles from one OHV 4.0 I could do it again. Between us we have already put another 6000 miles on the 98. Mark