The more tired the more likely to make mistakes the longer it takes more tired. Among other things - no sound. I spent ages reading up on the why and how. It was just that I hadn't installed something I assumed was there and therefore hadn't checked. Plus variations on that theme. They were solved. I have to be up in 4 hours. If someone rewrote The Pilgrim's Progress except instead of a book Christian had a laptop, The Pilgrim's Progress would become a dark satire of social media and man's relationship with technology. It will be much quicker when I re-install tomorrow night.