Much of the information you need about class registration can be found at the university's Office of the Registrar. Check there for information about:
If you wish to drop all your classes before the term you are registered for has begun, you may cancel your registration.
If you wish to drop all of your courses after the term has begun, you may withdraw from the university. If you withdraw, you might be entitled to some refund of tuition and fees, depending on the timing. ACES students should use the Withdrawal/Cancellation Form, and submit it to 128 Mumford Hall.