Game locks up for a period of time, (including the rest of `computer) and ends with a graphical error, that may cover the entire screen or partialy,
Same as a above, your walking along anywhere and it happens, you can reset it by simply switching from fullscreen to windowed, but certain areas may be more problematic than others, certainly cities full of people experience it more often than an instance. its important to note that this glitch affects the entire computer, you can not do ANYTHING when this happens.