Toshiba Satellite laptop's display spontaneously goes black as if it is going to sleep or being turned off. Most of the time when the touch pad is contacted or the enter button is pushed the display will come back up. But every once in a while there is no way to "wake" it up and the unit needs to be shut down by holding the power button down. Power settings are set for the display never to go off or go to sleep. I am running the unit with the power cord and no battery in place.