Some info would be nice. Year and engine size would be cool.
So the spark plugs spark? For sure? The fuel pump runs? Even when it's cranking? Means its got spark and fuel. So that leaves compression issues (todays engines usually never have air issues that cause a complete no start, unless it's a sensor, so I am omitting that), and it would seem to me the timing belt either skipped or is broken.
Yet, it could also be a sensor. It might be a Crank Angle Sensor or a Crankshaft Position Sensor gone faulty. Also, does the CEL light up at all when you turn the ignition to "ON"? If it doesn't, I'd suspect a PCM.