yesterday i was playing guild wars 2 and all of a sudden, lines started coming out of everything. So i shut the game down and there were these white pixel or dots everywhere on my screen. It doesn't seem to go away even if i reset my computer. I disabled my graphic card as a test and they went away. Specs:
HD Radeon 6870
4 GB RAM
AMD Phenon(tm) II X4 955 Processor
Have you done any overclocking? Seems like you have artifacts. It could be that you PSU is not good enough for your GPU or you pushed you GPU a but too hard it over heated and now it's damaged. I suggest you try you video card in a friends computer.