So I found a perfectly good working iMac at the dump. My guess is that it is a 2008 model or so. Booted right up and I was in the computer messing around. Had to run some errands and when I came back it now asks for a password to get into it. Not sure why I was originally allowed access but whatever. I know Apple's security is legendary and figured I would need to wipe the drive and re-install the OS anyways. So I wiped the drive and I am trying to install El Capitan OS which is what was on it. But I cant do it with it burnt on a DVD. When I try to do it via the internet it says something like "file is currently unavailable". Any help would be greatly appreciated. Thanks.