I have an HP laptop and when I start it up it will bring up the login screen and these black flickering lines will start on my screen from left to right all over the screen and when it gets bad the entire screen will go blue with black vertical lines they don't move or anything they are just there and I have to restart my computer and then its fine can any body give an answer as to what it is? And why it happens? I have windows 7 if that has anything to do with it