I was working in photoshop last week and noticed that the mouse/wacom was acting sluggish and then all of a sudden my Cinema Display 27 went dark and never recovered. Since then I've been resetting all I can without the aid of a display and tried to reinstall osX by disc but no luck. I was thinking is was the Radeon HD 5770 but wanted to see what the community had to say. I am attaching an image of a lit red diagnostic LED if that helps. Thanks for any and all input on this issue.