Click START, select RUN and type <b>dsa.msc</b> then click enter.
If you want it back into your Administrative Tools, you can create a shortcut to the above console.
To do that, go to “control panel”->”administrative tools”
-Right click on any unused space of the right side window, and select “new”->”shortcut”.
-In the target or location, write: %SystemRoot%\system32\dsa.msc
-In the “start in” box, you could put something like %HOMEDRIVE%%HOMEPATH%
-You can add a comment also.
-Change the shortcut name to ‘Active Directory Users and Computers’, and you are done.