Yeah, I was just being sarcastic as there could very well have been somebody who was going to come into this thread and post a useless comment just to be a pain. So I thought I'd say it as a deterrent 😉
I've had a quick read around and, in addition to logic, it is more than likely going to be a hardware issue with the display, as well as the fact the whole line is blue, suggesting that a component has died within the display or is badly malfunctioning.
As JohnStar said, try an external monitor just to see if it is a graphics card problem; however, this is extremely unlikely.
Honestly though, best bet is to take it to a reputable repair shop for them to take a look, in the odd event that it isn't a issue with the display directly.