Are you referring to the Menu Bar? You can turn that on by typing MENUBAR at the command line and changing the value to 1. You will likely be disappointed by the results in AutoCAD Architecture, however. Since going all ribbon, all the time in the 2010 release, the Menu Bar menus were removed from AutoCAD Architecture. If you have the Express Tools installed, you will have an Express menu there. If you have any third-party customizations installed, there may be a Menu Bar menus for those, as well.
AutoCAD (ACAD.cuix) still has the AutoCAD commands in the Menu Bar; you could transfer those to the ACA.cuix or to a custom customization file (and then load that custom file as a partial customization file) so that you can add the AutoCAD Menu Bar menus to your workspace.

David Koch
AutoCAD Architecture and Revit User
Blog | LinkedIn
