There is usually a strip of LEDs -- most often at the bottom but sometimes across the top as well -- that illuminates the screen. One LED looks to be out. The screen needs to be replaced, so contact Dell for a warranty repair.  
Hey, this is my first post on here so not really sure what information to supply. I brought an alienware area 51m 17.3inch laptop around may of this year, it works great till about a month ago when I turned it on and noticed in the center of the screen, there is a dim line going from bottom to top, the bottom area is a lot darker than the top. Originally, when I first noticed it, restarting, would solve it, other times it just corrected itself while I was using it.  However, for the last two weeks its been there constantly, nothing I seem to try helps it, I thought originally that it might be due to battery saver mode as when I checked the settings and changed them slightly it seemed to work for a couple of days.  Is there any solution for this? My laptop is fully updated, has all the latest drivers. Do I need to contact dell to claim a repair on the warranty? What happens when I do this? Mostly my laptop has been used to either play 7 days to die, or the sims, or just general browsing, occasionally using word so nothing too over the top. I appreciate all advise given and will try to answer any questions to the best of my knowledge, thanks in advance, Phoenix [IMAGE]   
Area-51m R2, dim line in the middle of screen