Theft deterrent

Plagued once again by trouble-----I've had the battery out of my 03 alero for a couple of days now,and when i finally got around to putting it back in the horn blares like crazy and all lights are flashing I know its the anitheft or theft deterrent but I have no idea on how to reset it,can someone lead me n the right direction.

Thanks

Did u ever get this resolved? I have the same issue

Leave your keys in the ignition (turn over, but don't start engine) leave it for about a minute with the alarm going off by itself.... a lot of cars will reset its self this way.

Thanks I will give this a shoot