In most cases, the situation is one of miscommunication. Work out the situation collaboratively with your supervisor. See your supervisor immediately. If necessary, the supervisor will go to the Ombudsman for advice on removing the student from the class. See When Communication Goes Awry, page 166.
Disruptive students are rare.
Sometimes students who have transferred from another college and who legally have met the requirements for your class in reality just aren't prepared. If you encounter such a situation, you have several voluntary options. First, bring the situation to the attention of your supervisor. If the problem is not ESL-related, the student can either drop the class and spend time with a tutor on a volunteer basis, or take a course at another school. Legally, a student who has met the prerequisites for your course has the right to stay in it.