I thought I would share a recent experience I had in case someone is going through something similar. Without any warning my Mac Pro would not start one morning. I did all the usual start up stuff with no good result. I could hear the start up chime and drives and fans moving but nothing on my monitor. I checked the monitor with another machine and it was fine. So I called Apple support and after a short conversation got an appointment at the local genius bar. Man what a zoo that place was. It was full of people trying to buy I phones. And teenagers playing with ipods. Well they took my machine in and said it is either the mother board or graphics card and it would be 10 to 12 days. That really bummed me out. The guy ordered both while I was sitting there and took my beloved machine back with all the other sick Macs. Six days later I got a call saying my machine was fixed and I picked it up within a hour. It has been fine since then and they even fixed another issue I had with the machine that I had created. Although it was disappointing that a part on a brand new machine went bad like that and hard having to go back to working on my old machine, I am very happy with the service I got from Apple. Oh, yeah. As you all suspect, it was the graphics card.