How do I keep someone from finishing the form if they answer a check box incorrectly?

Hi, I have a check box with the choice of "yes" or "no". If the person chooses "yes," they may continue through the form. If they answer "no," I want them to be notified that they may not continue unless the answer is yes. The issue I'm having is I don't know how to keep them from continuing through the form and I don't know how to notify them that their answer keeps them from continuing. How can I do this?

Thanks!