I switched out monitors at work yesterday and now my video out on my mbp is no longer working. I even tried the old monitor and it's a no-go. I do not have another mini-display port to DVI adapter so I hope it's that rather than the computer. The screen will do the "to blue" flicker as normal when you plug in a 2nd display - but nothing shows up on the second display. I was wondering, other than buying a second adapter, if there's a way to tell if it's the adapter or the macbook itself.