Hello leeanne19,
My name is Shrikanth and I work for the Social Media and Community Team at Dell. When was the last time it was working? Did you happen to make any changes? Please try updating the video drivers
http://dell.to/1lTHx4p also check the display by connecting an external monitor.
Thanks and regards
Shrikanth G
Social Media and Community Professional
Order Status :
http://dell.to/1mpzOt7
Download Drivers :
http://dell.to/1pkzznO