So I'm finally ready to reinstall OS X on my Macbook Pro, did the Time Machine Back up, did the command-R, found the screen to reinstall Mountain Lion (which is the OS X I want to keep for now), then got the error message "Temporarily unavailable. Try again later." Not kidding, that was the error message. So, contacted apple support who advised I needed to open ports in my router. I googled how to do this and found some info, but certain numbers are needed to fill in in the configuration page of the router. I can navigate the configuration page a bit, but need to know what numbers I need and how to open the port so Mountain Lion will connect and reinstall.