Looks like I have a broken iMac. First I unplug all the USB/FW devices I have except the keyboard. I hit the power switch, I get the "chime" sound, grey screen then grey Apple logo and then the little circle icon that rotates. It will rotate like that for hours so I turn it off. So my question is What is the Mac doing while the wheel is spinning? Looking for a boot device? Then why not say "can't find boot device?" I think the problem might be even more basic than a dead disk drive. How to figure this out?