1997 Chevy Lumina THE CAR WONT START

Engine Mechanical problem
1997 Chevy Lumina Automatic 180000 miles

MY CAR DOESNT MAKE ANY SOUND WHEN TURNED OVER. I TRIED REPLACING THE BATTERY WITH A USED ONE. I ALSO TRIED CHARGING UP THE USED ONE. THE USED BATTERY WORKED FOR ONE DAY THEN DIED TOO. MY AIR CONDITINOR DOES NOT WORK AND SOMEONE SAID THAT MAY HAVE SOMETHING TO DO WITH IT. OR COUD IT BE MY STARTER OR ATERNATOR. PLZ HELP BCUZ I LOVE MY CAR. THANKZ SO MUCH! I AM A YOUNG MOTHER OF 2 WHO NEEDS THIS CAR TO GET BACK N FORTH TO WORK