I have a 2008 MacPro 8-core (bought used from work). It came with 2 320GB WD hard drives, in bays 1 and 2. These two are working fine. I did have some trouble when I brought the machine home (got the "no bootable drive found message" on first boot). But I reseated the drives, reformatted, and finally managed to get Snow Leopard installed. Anyway, I bought a new 1TB WD drive to put in bay 3. It didn't even show in Disk Utility. I moved it to bay 4, same thing. Finally I moved it to bay 2 (and moved that drive to bay 3), and it showed up, but the other drive (now moved to bay 3) didn't. It seems like bays 3 and 4 are not functioning. Anyone ever seen this happen before? Any suggestions? Thanks in advance.