Lights

You will need to clarify the first part of this because I cannot understand exactly what you mean by it without seeing & hearing it for myself, but the beeping would or should not have anything to do with what you already mentioned. The beeping is usually an audible alert to a problem in a malfunctioning system, but since it appears to be related to the lighting, is would probably be due to 1 or more bulbs burned out or a short or something of that nature.

The dash lights, head and tail lights flash continuously, and it doesn't stop until all doors are shut and the car is shut off.

Ok, making progress now. That could be a bad lighting relay inside the black power supply/fuse box under the hood near the engine, or it could be the anti theft system in the car shorting out and screwing up. To check the relay, take one out of a ocket for one of the other systems in the car like the wipers or someting like that, if that system works ok with no problem. Switch that relay with the one for the lighting system. If your problem goes away, then that relay was bad, so just buy a new one to replace it. As for the anti theft system, are you using an original key that came with thye car? It actually sounds like you are using a valet key instead of a fully programed key. I had a Chryler van that the system went crazy in and would just not operate properly with the programed key so I eneded up disconnecting the system and no more problems. Good luck & let us know how you make out.

Thank you and I will