In any event, I ultimately found a solution that worked for me: I thought 'has Microsoft ever steered me wrong?' Before I could answer that question I hit 'yes' and never looked back). (Which I don't have of course - it just downloaded one day and asked if I wanted to upgrade.
I tried some of the solutions here too but most required access to a second computer, knowledge of computer stuff, or at least the windows 10 load disk.
Same exact problem - black screen, blinking cursor, no response. I am a complete computer novice but, as it turns out, that ended up working in my favor.