At school we have a classroom full of iMacs. They are PPC models, not Intel. They all netboot from a Mac OS X server. I can find out all the details and specs if I need to, but let me describe the problem to see if it's enough to get started finding a solution. The hard disk on one of the iMacs died. We replaced it with a new disk, and installed a fresh copy of Mac OS X on it. We set it up like all the other iMacs, as far as I know. It boots from the local disk just fine. It can see the server over the network and mount the network disk. It can surf the Internet, which it gets to over the LAN. But it will no longer netboot. If you hold option while booting, to go to the Startup Manager, you see only the local disk as a boot device, not the network boot image. If you go to the Startup Disk in System Preferences, the network disk is a solid icon, without a question mark, but if you select it and click "Restart" then the restart begins but never completes. The server offers to these client machines the same netboot image that it did before, because nothing on the server has changed. The other iMacs still netboot. So the problem must be on this iMac. The iMac's firmware has not changed (I tried resetting PRAM just in case, to no avail). Only its hard disk and the hard disk contents have changed, and I would have thought that netbooting from the Startup Manager wouldn't rely on the local hard disk anyway. As Detective Q, I am looking for the culprit. Who are the suspects and what other clues do I need to gather?