Green lines swarming my computer

[Maxi120]

I have seen a few things about this, but I'd like to make my own and figure out how to fix mine. I'm not a huge tech guy, so I might be a bit confused if you don't use easier to understand terms. Basically, my desktop has green vertical lines going through parts of it. It started off only with the start button, and then it spread to just about everything that was green. Recently (today) it started affecting red/orange. Luckily, blue isn't being hurt by it yet. Things like brown are though, since it has red in it. So that makes me wonder, what is actually causing this? I tried virus scans and it didn't find anything, and I have tried turning my computer off and letting it rest a while. Is my video card going bad? Overheating? I have next to no idea, so help with this would be nice.

PS: I tried to get a picture of them, and it worked at first, then it disappeared out of the picture.. ._. Why did it do that? (took a screenshot) So does anyone know what I should do?

Thank you for your help ^^

 

[Mark56]

Does this defect appear immediately you turn on the PC or does it get worse the longer you have it switched on?

Is this a desktop or laptop PC?

 

[Maxi120]

It does not happen immediately. It is off for a few minutes, then it starts up. It gets worse as it's on and your doing stuff, but it almost seems that if you leave it be and come back, it will stop, but once starting a game or something, it will get terrible.

It's a desktop ^^

 

[Mark56]

This sounds like your Graphics card is overheating. Check inside the PC to make sure the fan is running and is free from dust, try blowing it out with a can of compressed air. If it is overclocked return it to default.

What card do you have, there may be a temp read out available in its control panel.