What Version of the game do you have ??
What's the size of you mdf file (in bytes) ??

have you followed the steps i have mentioned above ??
you need to replace the created mds file with the one from the Daemon Side.
Do you have the newest version of Daemon Tools ?? If not then get it.

When the CD-Cursor spins and nothing else happens, then the Program has noticed, that the orginal CD is not in the Drive.
The Program writes no more text boxes like please insert the right cd... since this is a weak point of a program where you can easily attemp to crack it.

Read the HowTo one more time and try again then write what happens.
Have you made the mds-Image from an other image(for example. bin) through Daemon-Tools or have you made it with your backup CD or with your orginal CD ??