Does your new installation of Autodesk Map 3D 2006 look different than the way you are used to seeing AutoCAD?

A quick check is to look for the Analysis pull-down menu and the command line.  A blue background is another give-away.  To get back that classic AutoCAD look, just go to the View menu pull-down and expand the Menu/Toolbar Layout cascade and select Map Classic. 

This opens some toolbars, that you can just close out, and several other changes, but you are back in the classic interface with the ever necessary command line!

The Map Explorer can be suppressed on start up by going to the Map menu pull-down and selecting Options from the bottom of the list.  In the Map Options dialogue, un-check Show Task Pane on startup and Show Display Manager on startup in the Task Pane tab.

A variable change should be made to all installations to avoid a possible corruption with some dialogue boxes, most commonly, the Layer Properties Manager.  Enter MAPSKINMAP at the command line and hit enter once.  This removes the silvery grey "skin" that conflicts with some dialogue boxes.

Finally, enter TBC at the command line and hit Enter twice to toggle the background from blue to white and then to a final black.  Tada!  There is that classic look and feel once again!