Hi all, I have a late 2012 iMac 27", which I have set to enter display sleep in 5 minutes and the computer sleep to never. I tend not to switch off my iMac most of the time and I have only switched it off a few times in it's life. Earlier in the year, I was advised (on here, actually) that the HDD (a standard Apple-installed 1 TB SATA disk) was dying and that needed to be replaced. I am hoping to getting round to replacing it (with a 1 TB SSD probably) sometime this year. Another problem has come up now: I have found that if I leave my iMac to go and get a coffee or something, which usually takes me between five and fifteen minutes, the iMac display enters sleep (as expected), but then does not come out of this newfound coma, when I press any key on the keyboard. I have tried everything, including leaving it for a few minutes, holding the power key to try to force it to reboot, pressing the key commands for the Force Quit menu, but nothing seems to work. The display remains black and unresponsive to my commands. If I listen closely to the iMac itself, I cannot hear any fan sounds, or in fact any sound at all. How do I go about fixing this? Would setting the display sleep to never help me? Or is this another symptom of an ailing HDD? Thank you!