I already reported here that iTunes on WinXP turns off nVidia window transparency. This affects a lot of Dell laptops (many Inspirons, Precision M60), Samsung X10, ... I just found a way of restoring it : type ctrl-alt-del and open the task manager. Then close the task manager. Done, window transparency is back and the nVidia manager says the app that turned it off it closed! Don't ask me why...

BTW, this is really a crazy world: EOLAS just won... Everybody in the tech world knows they should not win but they won.