Part of this post is a laboratory notebook. I record how I fixed my computer, because
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I am pleased to have been able to do it, and
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I may have to do it again.
Briefly, when Windows on my laptop failed, I installed Ubuntu, but this failed. Somebody else installed Ubuntu again, and this worked for a while before failing. I managed to fix that problem for myself; but later an upgrade failed. Now I have fixed that. 
I am recording further issues in an addendum.
Polytropy 