what wrong with my sunroof?

My sunroof usually works just fine. It sometimes will open and close then finally close. More recently when I am on the interstate it sounds like its open, and sounds very windy. When I get out to look at it its only cracked very very slightly. It is not open. All I do is press the the glass down and its fine. No water leaks in. Just wondering if there is anything I can do to fix this rather than bring it in to the shop. I do have an extended warranty but its a $100 just to have it looked at.
Thanks.