My toshiba laptop windows 8 suddenly have a vertical line. I didnt do anything wrong about it. I only downloaded songs and dj app and it went fine all the way. After i finished using it I close the app. And refreshed my laptop. And then i did not shut down it yet because i still have something to do with it so i only press the power button in the keyboard area and close the laptop. When i get back in a few minutes i open it and press the power button and then i was shocked because it showed me the vertical lines on the screen. I cant see anything but vertical lines with it.
Assuming you already tried to reboot it and same thing happened after the reboot, could be a bad screen connection, failed screen, maybe bad video card/CPU, RAM issue can cause this, overheating. Really a lot of issues. If you don't have any experience in checking laptop hardware you will need someone else to look it over to troubleshoot.