Every now and then when I log-in my game screen blinks. For EXAMPLE, The dark outlines of words and shadows jumps from light to dark. some outlines get bigger them smaller. It's not my Graphics Card (GeForce GT 240 1GB), or could it be. Sometime when I log-out completely, then back log-in, the game functions normaly. This dose not happen all the time, but it happens enought to be annoying to the eyes.