What version of AutoCAD Architecture are you running?
AutoCAD Architecture does not include pull-down menus in the out-of-the-box ACA.cuix file, so not having a Tools menu is not a surprise. You say typing RIBBON at the command line and pressing the ENTER key does nothing. There is no message saying something like "Unknown Command" at the command line? If not, then nothing is exactly what I would expect from the RIBBON command when the ribbon is already displayed.
Does the top of your AutoCAD Window look anything like the image below? In particular, do you see Home, Insert, Annotate, etc. just below the Quick Access Toolbar?
If so, then you have minimized the Ribbon to tabs, so only the tabs display. If you left click on a tab, the full ribbon tab will display, and you can choose a tool. To restore the ribbon to full display, find the button to the right of the last ribbon tab name, and select it. (The red arrow in the image is pointing to this button in the image above.)
There are other minimize states: panel tabs and panel buttons. Panel tabs shows the names of the tabs of the currently selected ribbon tab below the ribbon tab names; hover over a panel name to see the full panel. Panel buttons shows a the panel names with the icon of the first tool on the panel in a "button". Hover over the button to see the full panel. If you are in one of these other minimize states, you can restore the full ribbon using the same button at the far right of the tab names noted above. If you are set to cycle between all ribbon states, you will have to click more than once to get to the full ribbon.
If that is not what you are seeing, you may need to try a repair install or a reinstall.
David Koch
AutoCAD Architecture and Revit User
Blog | LinkedIn
