if the unit under warranty then have dell send you a replacement. zif this is a laptop find out if the video card is part of the system board or a small daughter card. if it part of the system board then the system board would need to be replaced or the system ram. most gpu use system ram if one of the ram sticks is lose or bad you can have issues or it could be a overheat issues...one of the fans could have failed or is dust clogged. alsoi seen a few post of people having a lot of system board failures on google where people have had dell replace there units.