My boyfriends sunroof wont open up all the way.

My boyfriends sunroof wont open up all the way, when we hit the button to open it budges a slight bit then starts making an awful clicking noise until you let go. You can then push on it a little to get it to go up properly. Then when you try closing it it will go down but when you let go it continues to make that awful clicking noise till you hit the down button a couple times then it will stop. How do fix it so it will go up and down without any issues?