Over the last couple of weeks I've had a couple of problems with my screen. First when I change windows, I usual work with windows full-screen like I do on Windows, I get random squares of plain black for a few seconds like the image isn't being re-draw, although the old image is being changed to black. Second, most noticed when load these forum pages is the screen re-draws with text and images in the wrong places like the screen grab below. So is my video card failing?? If not what else could it be?