I bought a new battery last year and have had no problems...yesterday, when i went to start it, it just clicked..i jumped it off, started no problem, took it to autozone..they checked the battery...the battery is good, and they checked the alternator..it's fine too and giving off a good charge.. i went to start the car this morning and it started fine...I came home and turned it off, then tried to start it again...nothing...I can't figure this out...my battery connectors seem tight and the terminals seem clean. i have no warning lights showing on my dash...so someone please give me some advice!!

thanks very much