I was recently driving my car and park it and it wouldnt start up so I got a jump and it started up.Then a cut the car off and it didnt start again.That has never happen.Was thinking the alternater was bad.How do I check to see if my alternator is bad???
You need to remove it and have it tested. I am sure that someone here will tell you to start it and remove the battery cable - DO NOT DO THIS! You can fry the computer in the car, shock sensors, all kinds of nasty stuff. If the car is drivable at all some autozone type stores can test them in the vehicle.
A shop can test it best. But when you get your car running next time hold a wrench or some such metal object up to the back of the alternator. A good alternator will pull it with a magetic force.