I tested my alternator at advance auto parts and they said it was good. The guy later told me that it could be the voltage regulator. I later got a voltage regulator and replaced it. After i replaced it i got in the car drove it about half a mile down the road. I turn around go back to my house and cut the car off. I took the key out and tryed to crank it again. It hardly turned over. What could the problem be?