You have to replace the starter drive.
buy a new starter or go to a junk yard and find another one and replace it if the key keeps spinning you probably need a new lock and tumbler (you can pick them up at a local auto parts store).
A single click with no further spinning of the starter usually indicates a faulty starter relay/solenoid or a loose connection.
I have a 1997 grand am and i have power to the starter but when i turn the key over it wont in gauge the starter. all fuses are good. You may have a defective ignition switch.
The starter relay, solenoid or starter itself most likely is bad. If you hear clicking from the starter when you turn the key, then the starter is most likely the cause.
If the starter isn't working, the car will not crank at all. When you turn the key you will either get a clicking sound (which could also mean a dead battery), or you will hear the sound of an electric motor spinning and nothing else.
starter solenoid sticking
Weak battery Loose or corroded battery cables
See link.
Need to replace the starter. The starter drive ( BENDEX ) is broken. When you turn the key to the start mode it ingauges the starter and the shaft just spends inside of the gear that is made to turn the fly-wheel so engine will start.
BAttery?, starter? ignition switch?
you might have a loose ground wire.