I just installed Mountain Lion on the MSI Z77G45-MA and everything worked perfectly. I had a problem when I inserted my ASUS 8400GS graphics card and the boot takes 10 times as long and when I reach the login screen the keyboard and mouse do not work for about 5-10 mins then everything is fine. I have QE/ CI and everything is normall. It even recognizes the card in Mountain Lion. GraphicsEnabler=No I get a black screen. It must have something to do with the graphics card because it works fine without it. Here is the boot screen when its hanging. Anyone have any ideas? It would be greatly appreciated because I can't seem to fix it.