Did you try changing the display resolution? Change it. Right click the desktop and chose Properties... Parameters tab.
REDUCE the display resolution 2 or 3 notches.
If the line don't change, that mean that the screen is deffective and need to be replaced.
If the line's lenght or location did change, then it's a software isue, driver or something else.
Try updating your video drivers or roling back to a previous version.
If you installed some utilities or a new application, try un-installing it.
Electro, February 2012
