Why does there come a transparent line/cut on my screen?

[Cahilonius]

Why does there come a transparent line/cut on my screen? This usually comes when in a video the video moves, or when I play a videogame. Is this because of a bad video card, or a bad monitor?

http://imgur.com/l9BHlYB
Just above the eyes there's the line

 

[Ironsounds]

Hello... 1) First make sure your Video card settings and your monitor settings are set to 'native" resolution.
2) Try enabling Vsync if you have the option...
3) set your Video card output to the same HZ as the monitor.