Hi Ma32206,
Dell monitors automatically go into power-save mode after a preset amount of time when the computer is inactive. The Dell monitor will go completely black, instead of showing a screensaver. This allows your monitor to essentially turn off until it's needed again.
A. Press any key on your keyboard or move your mouse. Either will turn off power-save mode. Alternately, you can press the power button on your Dell computer tower or laptop.
B. Press any key a second time if the monitor goes from power-save to stand-by mode. Stand-by mode allows the screensaver to appear.
Bindu R - Microsoft Support.
Visit our Microsoft Answers Feedback Forumand let us know what you think.