I have a few seasons of Mad Men purchased from iTunes. Yesterday I changed my GPU in my Mac Pro, and ever since then I can't watch the HD versions - only the iPod formatted versions. When I try to start the HD version I get this message: "The movie "[insert title]" cannot be played because it is on a display that is not authorized to play protected movies." Is there anything that can be done about this BS? I've tried deauthorizing and reauthorizing my iTunes account, but nothing seems to work.