I have a 2001 cavalier.. I put a starter an igition and a nuetral safety switch in my car and when i go to start it the lights and the fuel pump comes on but the car wont start or turnover or anything.. Any idea on what it could be?

security, ignition must match key chip, check with ignition supplier for details on this,

I think its the theft system. Any idea on how to reset it?

there isnt a chip in the key, i have the same car and had the same problem, but in the mean time, I am jumping the solenoid to start the car because i have not found the issue. It is somewhere between the starter and the steering column. Next idea is to shim my new starter, even though i dont think thats it... Google bypass security or thft system and you can give that a try. If you wanna jump your solenoid, turn your key to the on pos. Lift hood and take a long screwdriver and touch it to the small bolt on the starter and twist up to the big bolt and touch the driver to both bolts at the same time and ignition will start. The big bolt would be the one your hot post wires go to. The ones with the strter relay on them. Hope I helped :) Amanda