I'm running 8.1 with the old-style desktop, not Metro tiles. If I switch to tiles, a big black rectangle appears on the LHS of my screen. In it is a big orange arrow and the words, 'Switch between apps. Swipe in from the edge to go back to the last app you were using.'
I'm using a laptop, not a tablet. I can't swipe.
Once the rectangle appears, it overlays the tiles screen; search results appear beneath it. When I return to the desktop, the rectangle stays. ESC doesn't get rid of it, nor do any other keys I can think of.
Could someone please tell me how to get rid of this unwelcome intruder?