Hi guys, So long story short, I have an older iMac, and it froze, I restarted it and it wouldn't start up any more. I would just get the Apple logo and the loading circle. I read online to try and unplug, press power for 5 seconds, then plug in, wait 10 seconds and turn on, then I got a flashing folder with a question mark. So, I tried to repair disk, but it wouldn't work. I didn't have anything that needed saving so i erased it, hoping to reinstall MAC OS X lion. After the erase I tried reinstalling Lion, only to find out that its not available anymore in the App Store. I tried just downloading a MAC OS X Lion.dmg online and put it into a USB hoping it would start up, nothing. I put it into the HDD i previously erased. Still nothing. When i look at Startup Disks, its does show either the USB nor the HDD. I don't know what else to do. Please help. Thanks in advance.