Last couple weeks in my 98 TOYOTA CORALLA, when i try to turn the key it sounded like the battery may be dead. On the 2nd or third try it will fire up. Then today I started it and while driving it was making a higher pitch humming sound. i stopped st an auto part store and turned the ignition off and it kept running and wouldnt turn off with several trys. opened the hood and felt hot. started smoking below the front part of the engine block. i had to disconnect the battery terminal to shut off, Any ideas on what to do next?