I have a 21.5" Intel Core i7 iMac with a 1TB hard drive (custom ordered from Apple). Got it in July 2011 with the extended 3-year AppleCare warranty. The only thing I've ever put into it was 8GB of extra memory, shortly after I purchased it.
Yesterday. I started hearing random clicking from the computer... for 5-10 seconds... and it would go away. Later in the day, I started to hear it louder and longer. Each time it happened, the little loading pinwheel would pop up and my programs would start to lag out. I turned off the computer, let it rest a while, and got on again. Did something similar this morning, but did not last too, too long.
Later in the day, I decided to convert over a VHS tape to my computer using an EyeTV Tuner. The VHS tape was a 2-hour recording. I went to another room to watch something on cable and left it to do it's thing. When I came back, the fan in the computer was going "VVVRRRFFFF!!!!!!" very loudly (I heard it the next room over) and when I came back in, I heard "click, click, click, click, click, click," etc). I was able to move the mouse a little before the whole thing froze up, but nothing on screen moved and the higher lefthand corner of the screen was missing the menu icons.
I pretty much assume that the hard drive it failing me for whatever rason. I had this happen to my PowerMac G4 in 2000, so I'm not too unfamiliar with the signs. I turned it off for a bit, and then when I started it up, immediately started backing up what I needed and deleting space so I can do a final Time Machine update on it.
ANYWAY... I don't know what to do at this point other than contact my local Apple reps at my earliest convenience to see what can be done to fix it... but I'm curious to know if a replacement might be covered under the AppleCare warranty? My Applecare warranty runs out in late July of this year, so I'm hoping they can do something for it. Outside of that, I'm not sure what kind of service/product fee there might be for a replacement. Has anyone experienced this recenty to know what how this is generally handled?? I did some moving things around a few months ago with my documents and I'm not sure offhand where my Applecare papers are right now, but I know if I look the serial up on the website, it shows as still active. Would I need to present them with the paper directly? Does anyone know?