Problem ongoing for a few months now. I do not have AppleCare on this machine. I've got a 27" iMac that will randomly shut down, be it in the middle of playing music on iTunes, while I'm typing a document or while the machine is simply in screensaver mode doing nothing. Usually the machine tries to instantly reboot itself. All too often, it cannot be rebooted and I have to let sit for quite sometime before it will even power back on. Lately the problem has gotten worse -- almost never reboots by itself. Finally, in the last few days, it just won't turn back on. Nothing. Dead, apparently. My biggest concern is that I have an unreleased music album from an instantly recognizable major client on the iMac's hard drive, not due out for many more months and still unannounced. I can't simply take the computer into an Apple store for troubleshooting as those files are worth and could cost me exponentially more than even a new iMac outright ever would. So, (1) anyone know what the problem might be and suggest home remedies? (2) If I still need to bring the machine into Apple, what do you recommend doing with the HD inside? If I remove it, can Apple still troubleshoot the problem? Is it possible for me to remove it? Should I get a new drive replacement?