Cheve cavalier turns over but wont start - 2005 Chevrolet Cavalier

change the distributor cap

check for spark

Check the alternator.

Start out by spraying a small amount of starting ether down the air cleaner. If it cranks and runs for just a few seconds at least, you probably have a fuel problem. Turn the key to "On" and listen: Do you hear a whirring noise, the fuel pump kicking in? If you do, then you need to replace your fuel filter. If not, you may have to replace the fuel pump. If the engine does not start up after the ether, you might check the distributor, make sure all the wires are plugged in. If they are, The coil may have failed.

When the key is turned to ignition there is a "Prime" mode that the computer rnus. the pump will only run for a few short seconds. If you crank the engine you should get power to fuel pump the entire time you crank the engine.

Take the cars serial number to the cheve dealer and get a new key made

Sounds like you are getting power to everything but the engine.
Was there a ground wire to the head that you may have left off ?
Hope this helps
Sam

Right hand side of the dashboard at the bottom. Pull the cover off & you will locate the fuses.

If you have a fuse box underneath your hood it's probably in there. It's normally located on the left corner right in front of the windshield. It will have a black box housing over it, take that off and the diagram of the fuses should be on the inside.

i had similer problem on a cavlier dizy cap had a hair line crack.Also ignition is earhed through 10mm bolt on wiper motor and that became faulty causing the car not to start .