I've played flute for 4 years now but suddenly, I tried to play the Bb scale and my D E and F won't make a sound!. It's not out of tune, it just can't make a sound! Well, the sound it does make sounds like a beginner playing the high D for the first time but its not quite like that!. Get my drift!? Bb, C, G, A, Bb are good so its not because I'm not blowing hard enough!. If I do blow hard, it sounds like a high note way, way out of tune!. My band teacher and my friends checked it over!. What's wrong!? and how much would it be to fix it!?Www@QuestionHome@Com