Yesterday my new 2.8GHz iMac came in (it is one of those special deal refurbs). I upgraded from a white 2.16 iMac. After running the computer for a while, it froze. There was a ... ticking/grinding type of noise (it was a pretty quick ticking). The mouse didn't move, no beach ball, but it was just totally frozen. The sound is what is alarming me. Finally I had to physically restart it, and it came back okay, the noise is gone, although it took like 5 tries to get it to pair with my bt mighty mouse. (Mouse settings also reset to default each time I play WoW!) So do you all think I should wait and see if it happens again? Or is the sound it made perhaps a sign of trouble? I dread having to pack this thing up to ship back, but I am already missing my old iMac which had no problems. Thanks for any thoughts!