In MS SQL Enterprise Manager, goto management, current activity, processinfo and click on the details option under the view menu.
This will list all the users logged in, what application they are using (Macola, Crystal, F9, etc). If you right click on a process and select properties, it will show you the SQL command they are currently running. You can kill the SQL session from here as well, but be hesitant to do so if the SQL command they are running is an INSERT or UPDATE or DELETE command.
You can also send the user a message from here such as "get your a*# out of Macola". Its a very cool utility.
Let me know if you have any questions.
Software Sales, Training, Implementation and Support for Exact Macola, eSynergy, and Crystal Reports