I have the new Mac Pro, and tried installing my second dvd burner (a LG lightscribe) in my mac. When I installed it though, and start-up, it hangs on the grey start-up screen. At first I thought this had to do with one of my second HD, but through process of elimination realized that it was the DVD burner. How do I install the second burner correctly? It seems like I need to move the pin in the back? What position do I need to put in? Could this be the problem?