To change a screen saver in Microsoft Windows XP, right-click on an empty area of your desktop, and select Properties on the shortcut menu to open the Display Properties window. Click on the Screen Saver tab, select a screen saver from the provided list, click Apply and then click OK.
If you are using Windows Vista, click Start on the task bar, go to the Control Panel, click Appearance and Personalization, click the Personalization option, and click the Screen Saver tab. Choose a screen saver from the drop-down list under Screen Saver. Click Preview to see how the screen saver looks, and then click OK.
In Windows 7 and 8.1, right-click the blank area on the Desktop, click Personalize, and then click on the Screen Saver option at the bottom-right corner of the Personalization window. Click on the down arrow under Screen Saver to select a new screen saver, click the Preview button to preview it, and click Settings to customize the screen saver. For example, if you select the 3D Text screen saver, you can type your own text, change its font, adjust the resolution and choose your favorite motion. Click Apply, and then click OK to exit the customization window and activate the selected screen saver.