Here's the gist, I've had this iMac for four years, I've replaced the hard drive after it failed, and I've been having a problem over the past couple months during startup. When I turn it on, it gives a long beep, the screen remains black and eventually I hear the dvd drive spin up and the screen remains black indefinitely. I restart again, no beep, but screen is black. Restart a third time, same thing as second time. Restart a fourth time, same thing. Restart on the fifth time, I hear the dvd drive spin up right away and the loading screen pops up. I've verified this is not a ram problem, it shows that I have all 16GB installed through the About Mac window. I've also reseated the ram in various arrangements.