If you haven't been officially admitted to a major, you must meet with your faculty advisor to review your plan for next quarter and get your registration hold lifted.
Schedule a meeting with your advisor soon as advising schedules can fill up closer to registration week. Information about your faculty advisor is found at Faculty Advisor Assignments.
Of course, it's still a great idea to meet with your faculty advisor when you've been accepted to a major or minor. Faculty advisors are experts in their fields and wonderful guides for students.