Hi, I'm having a problem with my Dell Latitude E6400. When I'm not using it for a while the screen goes black (like into a sleeping mode) like all computers and laptops do. But if it stays black for a little while, and when I go to get back on it and move the mouse around or press the keys the screen won't turn back on but the computer is running because the light on the keyboard are lit up and I can hear the fan running. The only way I can get the screen back on is if I shut it down by pressing the power button on my keyboard and turning it back on. Can anyone please tell me what to do or what is wrong with it. That would be much appreciated. Thank you Being thirteen doesn't mean I don't know what I'm talking about.