I have a white line vetically down the middle of my screen

This is a problem with your screen caused by excessive use, not turning the computer off or not allowing the display to sleep. More lines will appear if you continue treating it as you have; go into System Preferences --> Energy Saver and change the Display Sleep time to be shorter, like 15 minutes or so and check the "Automatically reduce brightness before display goes to sleep" box. Hopefully it will not get worse or you can live with lines on the screen, otherwise you will need to replace the screen which could cost roughly half or more of the cost of the actual Desktop.