When you perform a complex and time-consuming query in your ASP program, you should periodically test whether the client is still connected, using the IsClientConnected method of the Response object, as in :
' a lenghty query here
' check whether the client is connected before sending results
If Response.IsClientConnected = False Then
' stop processing if client disconnected
' else send the query results
Note that IIS5 has fixed a bug of this method. Under IIS4, in fact, the result from Response.IsClientConnected couldn't be relied upon unless you had already sent some output to the client.