Timothy D. Naegele said: >Beginning a few days ago, all of a sudden when I am working, the >screen goes dark like the machine has gone to sleep. Are you sure you don't have active corners on for the screensaver? It's easy to slip over there with the trackpad and if done quickly and the machine is working on other stuff the display may go dark for quite a while before the screensaver starts. What helps for me is closing the lid or pressing Option-Command-Eject or Option-Command-Power to put the machine to Sleep and then reawake it.