If you disconnected your battery or installed a new battery there is a reset button under the steering column. It is the red button hanging there. Press it and turn key to on for a few minutes,then it should start.
If you disconnected or changed the battery recently you have to press a reset button. It is located under the steering column. It is the red button, I think you have to turn the key to the on position then press the button, wait a few minutes and then it should start.