I am not sure what else to suggest, my friend. I would think that the button to get into the car would be the same one to get out. Somewhere along the lines, your settings may be corrupted. You may want to uninstall the game, and then reinstall, so that the control scheme is reset. Hopefully this can take care of the problem.

Otherwise, your best bet would be to go to that GameFAQ's site I gave you the link to in the other thread, sign up as a member, and post the question on their "The Godfather (PC)" message board. Since they have the PC game, they are better able to help you than I can, since I have the Wii version.