You’ll learn even more by fixing things w/o reinstalling.
I’ve found one of the culprits for the disk write error. It was a game which caused all the problems. Maybe my comment pissed someone off by endorsing that polygamy should be allowed or that men need more than one girlfriend. But this also leaves a question: can a game change the BIOS settings of a system?
It’s for the best if you stick to technical information in this forum…