hello all, i am using precise pangolin on an asus U57A-BBL4 laptop, 6GB RAM 750 HDD, everything works wonderfully, however, after i click on logout, my screen goes black, and its just stuck in black screen and doesnt logout.. On the flip side of things, if i select shutdown, it does that with no hesitation what so ever, any advice? it would be greatly appreciated, thanks in advance, Ali