Does your laptop screen go dark after you unplug the power adapter? The screen probably darkens to conserve battery power. However, you can prevent this from happening by modifying your laptop power settings. You can keep your laptop screen from leaving you in the dark by following a few steps.
Navigate to the "Start" menu and select the "Control Panel," "Hardware and Sound" and "Power Options." The Power Options dialog appears.
Select a power plan by clicking the appropriate radio button. If you select "High performance," your laptop's screen brightness is maximized. Note that this plan uses more energy than the "Balanced" power plan. Thus, this selection will reduce the amount of time that your laptop battery will last before needing to be charged.
Alternatively, you can customize the power plan by selecting "My Custom Plan 1." From the "Dim the display" selection, select from the drop-down selection the desired time that you want your display to remain illuminated on the battery. Select "Never" if you never want to dim the display. Click "Save changes" when done.
Allowing your laptop screen to display for extended periods will deplete the battery.