Ok. This is weird. My iMac screensaver was on. I moved the mouse, and the finder crashed. It would not relaunch. So, I did a force shut down. When I rebooted, the startup screen would get to waiting on local disks, and freeze. Boot from CD, no hard drive is installed. This is great. Take the iMac apart, and reseat the hard drive, and it is fine. Anyone ever see this before?