Toyota 1991 Camery Starting Problem

[qchen]

Hi, I have a Toyota 1991 camery 6cyl wagon. There is no problem before. After I let it sit for 3 monthes, the Battery is dead. I tried jump start but the car won't start. The lights do go on. I can hear the click from the starter and the fan seems to try to turn a lit. But nothing moves. Could you please tell me what may be thepossible problem. Thanks.