I have a 2007 Mac Pro with all 4 hard drive bays in use, 2 of them set up together as a mirrored RAID. I was using it as normal, when I suddenly got that "A device has been disconnected..." dialogue box. After looking in my list of drives, my mirrored RAID drives were no longer displaying. They weren't showing up in disk utility, so I tried restarting. The computer wouldn't boot at all, just got stuck frozen on the beginning white screen. Listening to the computer, I heard a clicking sound, so I thought maybe one of my drives involved in the raid had just bit the dust. I opened up the computer, took out out one and left the other in, the computer still would not boot. I put that one back in, and took out the other, and still the computer wouldn't boot. With both I heard the same clicking sound. I was able to get the computer to boot again by leaving both drives out. So now I'm not sure where to go from here. I find it difficult to believe that both hard drives died at the exact same moment. Are there any suggestions as to how I can determine if the drives are actually dead or if it's some sort of problem with the computer or the RAID?