Hi, I got my 24" white iMac back in the middle of July and I'm really happy with it apart from one thing it's just started doing. It makes this weird noise. It's not really loud but since I work in a very VERY quiet environment it is really noticeable. It sounds a bit like a hard drive or fan ticking but it's constant and is driving me nuts. One thing that's worth mentioning... possibly, is that if I'm in numbers working on a spreadsheet and I drag data from one cell to another, it stops! As soon as I release the mouse button to drop the data into another cell, it starts up again. It also stops intermittently whilst scrolling down documents/web pages. Has anyone else experience the same problem??? I have Apple Care but I am still in the complimentary 90 day's support window anyway. I purchased it middle of July from an Apple Store about 130 miles away. Any help would be most appreciated.