Cadillac Deville 2001 won't start, engine won't turn over
My cadillac won't start. When i turn the key the engine wont turn over and when i do turn the key all the way the dashboard lights all turn off. Also on the gear shifter there is no longer a line under the gear showing what gear it was in. If i move the gear shift up and down a few times hard-ish the line comes back so i put it back in to park and tried again and still nothing and then the line under the P disappears again. The line doesn't always come back after messing with the shifter. At first i thought maybe my battery was dead so i tried to jump it and after that when i tried to start it it still would not start. This time when i tried to start my car, it started beeping at me (the same beating that happens when you leave the key in) and locks the doors on itself, then, on the dash board screen it says "service theft system" then the over head lights started to flicker and the light on my dashboard for my brights lite up and started flashing and then stopped maybe 30 secs later. but slowly the battery died the rest of the way to the point that the dash didn't even light up at all. So i took the battery out from under the backseat and put it on a charger to charge. once it said it was charged i put it back in to see if it helped, it still wouldn't start. It is possible that the battery could be bad but i want to make sure its not something else before buying a new battery. It sounds likes its a mixture of a bunch of things and I'm not sure what to do. Help please.
