hey all, i'm having a very frustrating problem with my imac. it is randomly freezing up forcing a hard restart. along with the freeze is a terrible noise coming from the (external) speakers. if i turn the volume down, the noise goes away so i know it is not coming from inside the computer. the programs i use most frequently are itunes, world of warcraft and firefox. i initially thought it was a WoW related problem but the freezes happen when only using firefox or itunes as well. i took it to an apple store to have it checked out and it passed their tests. the real problem is that i cannot recreate the freeze to show them what exactly happens. sorry about the long read, but does anyone have any suggestions? thanks!