Car will not crank over

When my wife went start the car the the key would turn and all the lights come but car won't turn. The battery was replaced 1 and a 1/2 years ago. So I noticed the positive side of the battery was a little dirty so removed the posts and cleaned both the positive and negative posts and terminals, but when I went to connect the positive post it sounds like a alarm has gone off in the car but it doesn't a car alarm. Thanks, Dave Osborne