Question, need help quick
 

I took my dash out to replace the heater core, now I put everything back in. Well getting the dash out I had to move the auto shifter back to L, but when I had already took the dash halfway out, I would put the key in to move it out of P and it would make some beeping noises and then wouldn't move. I finally took the center stuff out and the shifter panel and moved it. Since I have put everything back in now the shifter won't move again and the car won't even begin to turn over, did I do something to the security system or is my battery dead or what the hell?