Little green dots?

I just bought a new HP Omni 120 All in One. And I seem to be having resolution or display issues. At the starting windows screen, before I get to the screen to put in my password to log in, the screen has all these little green dots all over. And then the dots are on the borders of borders of internet browsers. They were all over pictures and youtube videos too. I played around with the display settings and while it helped, it's far from perfect. So is this like a graphics card issue or something with the LCD screen? It wouldn't be much trouble to return this computer, but I just wanna know if there's anything I can do. Thanks.