I just started noticing an extremely high-pitched sound emanating from my computer even when it is turned off. It's the type of ring that you might hear after a loud rock concert (tinnitus). If I disconnect the power cable from the CPU, the sound fizzles out. Could this be something in the power supply? It's not as noticeable when the computer is turned off with the fans running and all. Maybe someone here has had a similar issue with their computer. Thanks!