My 2000 Ford Explorer makes a clicking sound (not a turning over sound) when I try to start it. THe lights, radio, and air conditioner seem to work fine. Once the car is jumped...which happens easily, it drives well.

Check your battery voltage when the car is not running. Check voltage again as someone else holds the key to START. Check voltage again after you've jump started it. First reading sould be about 12.5 to 13 volts. Second reading should be greater than 10 volts, and last reading should be 13.5 to 14.6 volts. If first two readings are low, your battery is not charged, or won't hold a charge (defective). if the 'while running' test is less than prescribed, then your alternator is not putting out enough voltage to charge your battery and should be replaced.