I have a 1996 Lumina base model w/most options. Daughter drove it to school, locked it with the remote, but left the lights on. It totally discharged the battery. The car locked itself up and the door keys would not work, the trunk key would not work. The remote would not work. Nothing worked. We managed to get the hood open by going under the front of the car getting it to release. Put a charge in to the battery and then everything worked.

Ay ideas as to why the car just totally locked it self to where none of the keys would work??

The keys would rotate in the door locks but wouldn't actually unlock the doors??
That sounds like a built-in trade-in indicator! LOL
Seriously, that sounds strange. If you ever do figure out how it happened, I'm sure we'd all like to hear about it.

Actually, The car used to be my wife's and I have now sold it to the neighbor's for their daughter. A 1996 Lumina, garage kept, 57,000 miles, dealer serviced its entire life was a great deal for them. I think the problem may be related to the fact that when I bought the car new, I had an alarm system installed on it. It eventually developed problems so it was deactivated by the dealer, but never completely removed. The remote still locks and unlocks, but does not activate the alarm system.

Actually, The car used to be my wife's and I have now sold it to the neighbor's for their daughter. A 1996 Lumina, garage kept, 57,000 miles, dealer serviced its entire life was a great deal for them. I think the problem may be related to the fact that when I bought the car new, I had an alarm system installed on it. It eventually developed problems so it was deactivated by the dealer, but never completely removed. The remote still locks and unlocks, but does not activate the alarm system.

I would recommend removing completely all bits and pieces of that add-on alarm.
They can be quite intrusive and prone to problems if not functioning correctly.