Whats wrong wih my 1997 Cadillac Deville? Anti -theft derrent issuse? Car wont start.?

[Uncle D]

I tried start the Cadillac and my DIC initially wouldn't light up or show signs of me attempting to start the car. Eventually the DIC panel came on and stated anti theft deterrent system problems along with service air bag. No start at the end. One day later I try to start the car and all looks normal this time but the battery sounds dead. (clicking noise from the starter was all I can get, not enough strength to turn over, just clicks).But powerful stereo sounds good.My DIC(electronic dashboard) say I'm at 12 volts or higher. Can I have power at the battery and stereo but not at the starter? What's the deal? Give me some troubleshooting tips. Thank You.