Either the monitor or video card are bad or the wrong software driver is being used for the video card or the refresh rate is out of range for the monitor. How to resolve it: Plug in a different monitor swap the video card into another PC or try a new one make sure the correct software driver is being used for the video card.
Or there is simply too much dust in the video card fan. Q-tips may be the solution.
A glitch or it is probably not responding/fast enough
If your computer screen has vertical lines on it sometimes your monitor or graphics card may be dying.
Eat your computer
u can buy them at best buy.
Your screen connector or your screen is failing in the laptop.
There are many reasons, but the most common of them all is the refresh rate. usually the best refresh rate is 59-60Hz.
I wound up throwing mine away. But that is just me.
Try going into your properties and changing the refresh rate of your monitor. It's probably set at 60 hz, try upping it to 85 hz. Also, check the settings on your video card, as they may have defaulted to something that is causing the lines on your monitor. Also, try using a bulb for lighting as compared to florescent lighting by your computer.
The computer should not have any vertical lines out of the ordinary on it, If you are talking about the inside of the computer its most likely standard floppy drive or SATA cables. I believe you might be talking about the monitor, and if you are than most likely the monitor is going out. Best thing to do is get a new one off of either newegg.com or tigerdirect.com you can find cheap/affordable to expensive models.
It is probably a video card, cable or monitor problem.
Calibration problems, or focusing issues.
i think.. this is depand on the defineaction of your moniter...