XPS 13 9310 screen is black

Hi. My XPS 13 9310 touch screen is black. Front light flashes 2 amber and 7 white. Ran D test and passed, but then ran it again and the colors were very dark, almost black. Laptop works fine with an external monitor. Upgraded to latest driver. The laptop screen is not appearing in the Device Manager, only shows the external monitor. When I restart the computer, the Dell logo appears very dark, then disappears and nothing else happens. Thanks for any help.