The cat just walked across my keyboard and the entire screen went black. I pressed a few buttons, including the on/off switch, but nothing happened. I was going to tweet and beg for an answer, but - oh, yeah! MY SCREEN IS BLACK!!!! After a few minutes of complete & utter panic - how do you feel when the tried and true method of "turn it off and back on again" doesn't work! - I realized that she had stepped on the dimmer key and just turned off all the lights to the screen. When I found the antidote, kindly depicted by Apple as a brighter sun, I fixed the problem with the computer. However, the cat is determined to get me away from the machine and reading my book! Enough of this "work crap!" It is a federal holiday, after all.