Monitor whines are caused by the CRT itself. The color guns are beginning to fail, and they will whine at certain frequencies. My wife's monitor would do it only when playing The Sims, but when she dropped back to windows, it would stop. Since I don't play The Sims (I play Emperor!) I swapped monitors with her. Well, it started on me all the time, windows or not. Finally, I just dumped it and bought a new monitor. 17" and 19" monitors are cheap these days, so if it is out of warranty, you should be able to get one at a local shop for a reasonable price.