<p>I would just move on from the C's and concentrate on getting the A's. Most Boarding schools (and colleges) look at how well you progress, if you improve with each passing year. You might have had a rough year but the only way to get past that is get good grades or at least work hard. Other than that, just try your best on the PSAT's or whatever test your taking to get into the boarding school of your choice, get some teacher recommendations, and work hard on the essays and you should be in pretty good shape.</p>