I searched the forum for some kind of answer but I havent found anyone with THIS particular sound coming from iMac. I have brand new iMac 24" and a few days ago I noticed really chilling sound coming from it. It sounds like high pitched, high frequency sound kinda like that piiiiiiiiiip in your ears comming from nowhere but your head or when you hear car-breaks disks squealing while breaking. Sometimes its just that, not very often, but sometimes its louder and more pronounced just as a thin metal plates spinning and touching would make (or at least thats what I imagine they would sound). It comes suddenly, something like ziiiiiiiiiiiiiiiiiiiiiip! And than nothing, until it comes again. I checked the temperature its about 55-58 deg. celsius. Other than that, the Mac is working great but it really scares the crap out of me when I hear it because it feels like the whole HDD will just explode or just die with a sudden screech. Any experinces, ideas?