Greetings! Was operating my iMac a couple days ago, everything was perfectly normal, then it froze. (As I recall, I had a web browser and a couple Finder windows open. After waiting several minutes, I did a hard restart. When powered on - iMac now chimes, shows the gray screen with the apple logo, and then shuts down. No failed HD icons or anything else. FW Target Disk Mode doesn't help, shutdown occurs before boot options interface can appear, safe boot results in the following screen (which remains responsive): https://twitter.com/AubreyFalconer/status/263690927778971649/photo/1/large Swapping both installed RAM sticks with a different set had no effect. Model #: A1225 Would appreciate any ideas for what I should try next.