Hi, My screen has been working fine and never had any issues. Last night i erased my data on partition and started to reinstall osx software, as it is going to be sold soon. The screen was working througout the insall of osx, but when i went back to check its gone black. I can switch the computer on/off, getting the normal startup sound and i know its at the set up screen as voiceover starts, but cannot see anything. Does anyone know why? I went from using yosemite to installing mountain lion, does this mean anything?