My laptop has been working fine until one day I walked away for a while, leaving it on and came back to find the screen "black".  After a while I noticed if light was shone directly on it I could faintly see the image of whatever file was open.  Under direct light and straining my eyes, the laptop will function fully as always, I just can't see anything.  Is there a repair or procedure I can go through that will restore the screen visibility?