In the past, you needed a screen saver, a continually moving display, to protect your monitor from burn in, which occurs when the same display remains on the screen for extended periods of time and becomes part of the screen. Those days are gone with the emergence of new display technology. Screen savers are more for entertainment than anything else. When you leave your computer idle for a specified wait time, a screen saver displays a continuous scene, such as an aquarium, until you move your mouse to stop it.
Select a Screen Saver
Right-click a blank area on the desktop, and then click Personalize.
Click Screen Saver.
Click the list arrow, and then click a screen saver.
Click Settings.
Select the options you want for the screen saver, and then click OK.
Click Preview to see the screen saver in full-screen view, and then move your mouse to end the preview.
Specify the time to wait until your computer starts the screen saver.
Select or clear the On resume, display logon screen check box.