My formatting Hard Drive operation was supposed to end tomorrow but it was cut short by the blackout which lasted several hours. So anyway in the end I decided that my approach was flawed. I deleted the partitions on the HD and did Quick Format. Now it doesn't give error messages any more. But clearly it still is not ready for use so I started the error checking utility. Hopefully that will help. It's not as slow as the formatting went but also quite slow and thus I contemplate another night on the sofa.