Don't dispair, the "It does-nothing" problems are often the easiest to troubleshoot. The less obvious and intermittant problems are the hardest to find.

Please supply a little more background and description. Did anything unusual happen right when the problem started? Did it fail suddenly, or degrade gradually to present condition? Any recent repairs - Ignition wires are back on in the right order, aren't they? Please add a little more info about the specific behavior when trying to start -- Does it try to start? Crank fast? Crank Slow? Make funny noises?

Review the basics of an IC enginge:
Fuel + Compression + Spark = Run (or at least an attempt to run)

Sounds like you have verified that there is fuel getting to the fuel rail. Double check to make sure that you hear the main pump running when cranking.

Compression: If the problem occurred suddenly, the timing belt may be broken. Verify by removing the oil filler cap and checking to see that the cam is rotating when your helper cranks the engine. Note: even if not broken, it may have slipped on one of the sprockets and timing is off enough to prevent starting.

Spark: Confirm that the ignition system is supplying spark to the cylinders. Easiest way is with a timing light, but if not available, check by installing one of the old plugs on the end of one of the ignition wires and place the body of the plug against the block. Don't hold onto the plug, just rest it on a stable spot on the engine block. Have someone turn it over and watch to see that a nice white spark appears between the electrodes.

Report back with your findings and get an update from there.

Good Luck,
Dan