Scrolling the screen with the mouse wheel causes it to move in c 1/3 to 1/2 screen-height jumps. And it takes its time doing it. Horrible.
I restored back to an earlier date, it's better but still I'm showing symptoms of the system being generally slow. It coincides roughly with me altering the power settings. I just wonder if I've missed something in resetting them - been over them several times.
I don't know why that icon just appeared, or indeed if that Intel driver is original.