My mac pro won't boot, all I see is colored snow and patterns on my screen. I verified that my monitor is still good. I can't seem to get the DVD player to open, to try to boot from a disk. I swapped out the primary drive for another, but I still have the same issue. I do hear the startup sound when I boot. Is there something corrupted in the startup disk? Or is there some ROM that assists in the boot up that is corrupted? Any ideas on how to troubleshoot?