What is wrong if the car will jump start Ok but the motor dies when the lights are turned on?

It sounds like the battery only has enough of a charge to run the ignition and the alternator is not contributing anything so as soon as you put additional load on it, the engine dies from lack of power for the ignition coil. If you have a volt meter, check the battery voltage BEFORE you start the engine. If it'needs a jump-start again do so and start the engine. Then remove the jumper cables and test the voltage level in the battery with the engine RPM at around 1000. With the engine running it should be somewhere near 13.5 Volts. If it's anything less than 12 V, you have a problem with the alternator.