Copy the Express folder and files to C:\Program Files\AutoCAD 2004

Copy the files under the support folder (do not copy folder just files) to  
C:\Documents and Settings\???\Application Data\Autodesk\AutoCAD 2004\R16.0\enu\Support

Then, go into autocad and go to the tools pulldown menu\customize\menus and click
browse...highlight the acetmain.mnc file and click open this will take you back to the 
menu icon and there..hit load to install the express tools menu. Then hit close.

Next go to Tools\customize\toolbars and you should be able to turn on the express
toolbars.