When you click Preview (or Refresh), Crystal submits the SQL statement to the database server.
Then Crystal waits for a response from the server. (ie Reading Records)
The "Not Responding" message shows up because Crystal can do nothing until it gets a message back from the Server -hopefully your result set.
Depending upon the version of the database you're reporting from, you can try turning on "Perform Query Asynchronously"
This will let you click the Stop button in the upper right hand corner of the Preview window. Crystal will then send a message to the database, asking it to terminate the query. If the database supports Asynchronous querying, it'll stop and return control to Crystal. If it doesn't support Asynchronous querying, then it'll ignore the request from Crystal and continue on its merry way.
This doesn't help you with the query you've got running now, but may help in the future.
Cheers!
Bob Suruncle