The title pretty much says it all. I have two different SATA drives that worked fine before in this computer and now neither one mounts when I put it in internal SATA slot B in my G5. I guess to be absolutely certain that both drives didn't simultaneously fail, I should move the drive that's in A (and is mounting and working fine) to slot B (and also try the spare SATA drives in slot A) to make sure it's the Mac and not the drives. Considering the extremely low chance that the problem is two completely unrelated drives dying while sitting in their boxes on my shelf, I have to believe that the problem is the cabling/motherboard that controls slot B. Neither spare drive will mount nor are they visible with disk tools. I ran the hardward diagnostic DVD and it reports no problems. Is there something else I should try before packing up the G5 and taking it to the Apple store?