2003 Cavilier 5speed won't start. Why?

start by checking if the bendix in the starter engages on the flyweel.

Starter is bad!!! If its getting the power to spin, then the arm will have power to engage the gear into the flywheel. In some cases there is no arm the gear is engaged from the starter turning. As it spins the gear heads down the shaft via a spiral groove cut into the shaft. Either way the starter is bad

1 more very unlikely thing could be the teeth on the flywheel are gone whether ground or broken. Does it always do it (I'm assuming u push start it)