Lately my computer has been making two odd noises. The first noise is that of wind whistling, and the second is a soft thumping/clacking sound that I can't describe. It makes these noises over and over again. I know the hardware itself is okay, because these noises are emanating from my speakers and go away when I mute the sound. I have no programs open that would make these noises, and they won't stop. What the hell is wrong?