Favux, Thank you once again for being patient and trying to explain things to me, but I think that you may overestimate my competence a little.
I went back to the first page of this thread and copied the lines into a terminal (scary!) but got as far as the second line in the second box and it told me that it would not do that bit.
I think that it will be so long Ubuntu, hello Windows within the next 24 hours.