Having seem an earlier post about trouble with an Acer laptop I thought I should ask for assistance on a similar problem. Cougar, Win XP 3. I, too, am inclined to leave my desktop on 24/7 (tut, tut) but on occasions when I come back to it after a routine automatic Win Update I find a black unresponsive screen with a white mouse cursor arrow which responds to my mouse but that's it. Only way out is to turn machine off at back and then turn on again. Any idea why. It doesn't matter too much but I don't like turning machine off.