I found that every now and again, mainly on web pages and games, I seem to get flickers of graphic glitches and I see pixels on my screen. I have changed monitors (both being 1080p) and still get this. I have updated my drivers and got a new graphics card and checked my cables and that isn't the problem, do you know what it is?
Sounds like what I had last year, it turned out that the graphics card had gone faulty. The only solution was to get a replacement. I think you have the same problem so it looks like you may have to get it replaced. Try running with the on board graphics to see it is definately the graphics card, just incase I'm wrong and it turns out it's something else, but I'm about 90% sure it is.