Car generally starts and runs very well ( only has 75k miles). Occasionally after a drive and stop, car will not start - acts as if totally dead. No clicks or any sounds as key is turned in ignition switch, no starter turning, etc. Problem can be solved by disconnecting and reconnecting battery. What component is likely source of failure. Igition switch, transmition switch, starting relay, ????? Diagnosing advice very much appreciated. Thanks.