I just bought a 2000 Grand Prix, about 2 weeks ago. This is my first, fully loaded vehicle, and still learning. My doors automatically lock, when I shift out of Park, but can only shift with my foot holding down on the brake pedal. The doors unlock when you shift into park. Not sure about the alarm yet, did go of twice. First time, I was just messing around, trying to get it to go off, had to tap on the dash a few times, the horn beeped twice, lights flashed. Second time, just got home from work, was gathering my stuff, getting ready to exit the car, when the alarm went off. Pushing buttons on the remote didn't shut it down, putting the key in the ignition, didn't do it either, pushed the lock button on the door, and it stopped. Should probably read the manual sometime...
Was wondering if your remote could be causing the problem, maybe weak battery, worn buttons. Would also go through and check as many connectors as you can find, see if any came loose. You didn't mention what car, or particulars of the accident. Might help use figure out what may be damaged. I had to replace both passenger side power window regulators/motors, which entailed removing the door panels, and several wire connectors. On the front door, the window switch came apart, rather than disconnect. Fortunately, it wasn't too tough to get it back together, but did learn that you can't operate the window, from the driver's side, without the passenger's side switch connected... Door locks could be the same way. Also have a child safety feature, which disables the windows and locks buttons, except for the driver's buttons...