LCD display that warns if the door is open is not working properly

Yesterday, my husband was driving my car and the front LCD display that tells when a door is open started weirding out. While my husband was driving it started flashing that the emergency brake is on, it's registering that the doors are open, and that we need to check tire pressure. He gets home and parks it and two hours later the horn starts blaring and won't stop. We ended up having to disconnect the battery to cease the constant horn blaring. I left the battery unhooked all night. Next morning I reconnected the battery cable and the horn immediately started blaring again. Disconnected the fuse for the horn and now the headlights are blinking and the doors keep locking and unlocking. We don't know where to even begin. I am a college student, there fore we do most of our own mechanic work. Please help : /