Originally Posted by Scavanger
Well.. she said the drivers side door, and the passenger side rear don't open.
Oh, joy. I had this problem with an '84 Regal that had been sitting outside for some time without being opened, and the driver'* door wouldn't unlock from either side.
Problem turned out to be a little spring-loaded plunger thing on the _underside_ of the door latch inside the door. It gets pressed in whenever you lift/push the outside door handle/button, and is supposed to release when you let go. If it doesn't, and stays stuck in, you can't unlock the door.
If you want to see what I mean, on a working door, have someone outside lift up on the door handle while you try to unlock the door from the inside. You can't do it until they let go.
I was lucky: on this car the interior door panel is in an upper half and a lower half, and I was able to unscrew and pull off the upper half without opening the door. This let me get inside the door and put oil on the underside of the latch, where the spring thing was, and work it in with my fingers until I could get it to let go. After that the door worked fine.
Basically if you can get a long nozzle inside the door any way at all, and blast the hell out of the latch mechanism with WD-40, Liquid Wrench or any thin solvent at all, it should work loose sooner or later.