Line going across the screen on top that doesn't go away

There could be a dead or stuck pixel that is creating the line look closely at the line and see if there's a dark spot on the line darker than the rest of the line once you find it take the eraser end of a pencil and apply a slight pressure to the screen on the spot then release try it a few times if the pixel is stuck it can cause it to release and the line will go. If the pixel is completely dead then the line will remain .In this event the only recourse is to replace the LCD. Hope this helps