Getting the above error on a Dell Optiplex 755. Either message stops the PC booting randomly from cold. Warm booting usually works after that, although the user said it didn't work one day.
Tried flashing the BIOS from A10 to A17. Swapped SATA cables. Same.
On the 755 the HDD and DVD are both SATA. But why doesn't it boot with the DVD channel error?
I'm going to try another HDD, but suspect is a motherboard fault.