Flashing the BIOS seemed like a good idea. The current BIOS in this motherboard (my second) is 1.80. The instructions were slightly different for each version that I tried but after trying to flash two different versions, 1.20 and 1.70, I gave up. Comments that this was not for this board were received and there's not a lot can be done when the software refuses to co-operate but at least it didn't kill the PC.
I do still suspect that there is a BIOS problem because there is no mention of SATA in the BIOS pages and why won't the software let me flash it again? Something not quite right! Have to get the thinking cap on again or maybe I'll give up and try a different manufacturer motherboard but that can get expensive especially if there is no difference.