My 94 Caddy Won't Stop Running!!

I have a '94 Cadillac DeVille that I bought with 130,000 miles. For the past month or so I have had this problem where my car will not stop whenever I want it to. Sometimes if I drive it a little longer it will let me shut it off. The only other way of turning off my car is by unfastening the screws attached to the car battery. Somehow that turns it off. This is really annoying me. Any help would be greatful.

probably an ignition switch bad or out of adjustent. or the ignition rod is bent check it out...common problems