Prevent duplicate registration

I see you can prevent duplicates based on IP address but I have clients that register multiple students from the same pc. How can I prevent them from enrolling the same person again? Is it possible from a calculated field (LastName, FirstName) or is there a better solution?

You can restrict the form so users can not submit the same answer twice on a specific field. If the enter the PREFERENCE wizard

Under the ADVANCED tab, you will see the UNIQUE QUESTION option. Select the field which you wish to limit the form.

Please let us know if this helps.