Black screen after blue Welcome my first name

[antonyp]

Upgrade-Windows10 installation 'over' Windows 7-worked right through till the last "Enter". I had a nice blue Welcome. Ever since, it repeats, but then always goes black, with a moveable but useless cursor. I cannot follow instructions. On restart, the Compaq start-up black/red figures appear very quickly, but have no effect. What to do?

 

[Saga Lout]

You might benefit from the StartUp Repair options but as your system thinks it's working properly, the trick to invoke it is to press the power button for eight seconds to shut it down. Sooner or later if you do it often enough, it will show those fixit options. The screen resolution might be out of range and StartUp repair could help.