So, you are actually running AutoCAD Architecture 2011, and not regular
This forum is for vanilla Acad which is why you got the answer you did.
In ACA, there is no other workspace option. You're forced to use only the
ribbon. The ACA.CUI has no toolbars/pulldowns or other workspaces defined
If you loaded ACA with the option to install a shortcut for the "Run as
AutoCAD" profile, then you will get the plain AutoCAD look with the ACAD.CUI
loaded (but still with the ribbon on by default). There, you will see the
other workspace options, including "AutoCAD Classic".
Unless you know how to transfer all the toolbars and pulldowns from an ACA
2009 installation which was the last version to still use pulldowns and
toolbars. Look into the "Autocad Architecture" forum. If you are using a
newsreader, the forum group title may be misleading since it's called
"autodesk.autocad-architecture.2008", but it covers all versions since 2008
including the 2011 version.