Dell laptop says it is doing diagnostics at boot up, but doesn't. Windows 10 did not start correctly because it shows the blue screen "windows 10 did not start right, needs to restart" box and "choose advanced repair options" box. When choosing restart, first a message" the media content you're looking for isn't there anymore" and then a black screen with a single window appears. When choosing advanced repair options, a loop back to the blue screen happens. It won't go anywhere else.