The best way to explain this is to just show the screenshot, so here it is
Image Link
The black boxes were added by me to conceal identity, but it's the black lines that are the problem. It is not application specific, and I'm not sure if they change at all or stay the same since I am yet to experience this myself. It's fixed by a reboot but it keeps coming back!
We can rule out the monitor, since it appears on the screenshot, so my best guess is video card issues. Anyone seen anything like this before or know what could be causing this and how to fix it?