I really thought I'm the only one has that problem.. It happened to me few times,when it crashes -I can't click on my desktop and even if I ctrl-shift-esc , can't click because it only has gunz on it that is not working. So I need to restart or sometimes wait for few minutes to make it back to normal. And about the alt-tab, it's not working sometimes, when I'm in-game- I can only see the score table than my desktop and in a few minutes it'll just crash.
