If it has an automatic transmission, I'd check the neutral safety switch. It should be acivated by the shift leaver or the linkage. If it has a standard transmission, I would check the safety switch activated by the clutch pedal.
check starter
if the battery is good, it is not the regulator.i would check all fuses first,then check starter solenoid and starter
Starter that is going bad, out of time, or weak battery.
Have you checked your battery. My battery died on me all of a sudden and I could not start my car.
There is no battery in the starter.
Possible causes include a weak battery, battery connections, and a failed starter.
bad ignition, bad battery, bad starter, need more info in the question
Make certain the cables from the battery to the starter and the body are good...may be a starter check out your local library for a shop manual and the checks to make.. d
If the starter is "clicking" then check the battery to make sure that is has enough juice to turn the starter. If the battery is good. It could be your starter solenoid is bad. Most of these are built into the starter nowadays. You will have to have the starter changed. I am betting on the battery especially if it is older. Another culprit could be your alternator failing to charge your battery.
check your battery. if your battery is Ok have your alternator and starter checked at a local Autozone or similar store
Causes include a weak battery, loose cables, failed starter.
Weak battery?Bad starter?Timing set too far advanced?