97 crown vic wont turn over or crank!! help!!

I was driving home and i turned off my car as soon as i put it in park. Came back down two minutes later and it wont turn over or try to start. It makes a weird low clicking sound once the keys are taken out of the ignition. Can someone tell me whats wrong???

I had a 97 and I would suspect the charging system--Fist thing I would do is charge the battery and see if it turns over and starts---It may be as simple as changing the alternator or battery. You can get either one checked out at autozone for free. You can get a junkyark alternator on ebay for cheap if need be... Let us know how it goes.