Dead Legend Need Help Asap!!!!!

I have a 90 Legend and its been dead for like 3 yrs now in the garage. The last time it was running i remember it had some battery problem and it died but we fixed that already and it worked? Then just few weeks it died again so now it wont even crank up. When i turn the key its just silent. What could be the problem? HELP ME ASAP...THX......:disappoin