On Sun, 26 Jul 2015 at 10:59 Craig Sanders <cas@taz.net.au> wrote:

do you get the same error if you edit /etc/fstab to refer to /dev/sdc1 ?

Yes. Except now for sdc1, not sdb1

ps: if you haven't already done so, check the power and both ends of the
data cables for the drives - loose connections can cause all sorts of
annoying intermittent problems.

Good suggestion. I have never opened up this computer, probably should check.

Also disks are standard SATA, I think the BIOS should detect them and power them up.