Cannot get my 1984 500sec to start this morning (or last week for that matter). Car has been sitting for about a month - it had its last run of about 80 miles then with no problems. When I try to start the car all I get is a rapid and noisy clicking noise like a loud typrwriter that has gone totally psycho This seems to be from underneath the car although its quite hard to pinpoint. I have tried jump starting the car from a spare battery but all to no avail. The seat belt extenders are working and the interior lights, so the battery may not be that flat. Could the starter motor be stuck perhaps? It has been sitting in the open all this time and I'm open to any advice or suggestions. Regards, Mark S.