Yes, another "my iMac won't turn on" thread, and before you ask: yes I tried everything in the book, and yes I used MRoogle to try find an answer first. So, here's my problem; I put my iMac in sleep mode and left it for a couple of hours. When I returned I pushed the return key to start it up. The screen lit up, as usual however the window requiring me to enter my password never appeared. I thought maybe it was just being a little slow so I went off and made a coffee. When I returned the window still wasn't there and pushing random buttons on the keyboard and waving the mouse around wasn't doing anything either so I held down the power button until it turned off (probably a bad idea). I left it for a few minutes before pushing the power button again. I heard the noise of the fans starting up, and the hard drive did it's little buzzing thing, and then all went quiet. I could feel the machine humming when I help my hand up against it but the LED's behind the screen never lit up. In the end I help down the power button again until the humming stopped. I've tried several times now to start it up, always with the same results. As I said, I've tried the stuff in the book like holding down option+command+p+r, and unplugging the power chord. I even left it unplugged overnight but still nothing. Any help would be GREATLY appreciated. I'm being forced to use my old Windoze laptop to post this. It's horrible! Oh by the way, it's a late 2007 aluminium iMac, which I bought early this year.