Frustrated and need help! Last week, our brand new (less than two months) iMac turned itself off, and when I went touted it back on, it would not start. There is just a plain black screen. You can hear the power coming on, but it's not booting up. I called apple, who tried to help, but they told me to take it to a repairer....s I di, took it to one of their apple repairers. He told me that there was corrupted files on it, causing it to not boot, and said it was not a warranty thing, so we had to pay $145 to have it sorted. He suggested that we just need to have an external hard drive to back up with time machine? Anyway......fast forward to tonight....it's done the same thing again! Turned itself off and won't boot back up.......any suggestions at all? I'm going to spit chips when I call them tomorrow! TIA