To change the screensaver in Windows 7, open the Personalization settings window via the Control Panel, select the desired screensaver from a drop-down menu, and modify the display parameters if necessary. To use custom screensavers, download them from websites such as ScreensaversPlanet.com and install them.
To access the Personalization settings window, click on the Start button, click on Control Panel, and then click on the Appearance and Personalization link. Click on the Change Screen Saver link in the Personalization section, open the drop-down menu in the Screen Saver section, select the desired option, and click OK. To test the screensaver before applying it, click on the Preview button. Select the time period before the screensaver appears by entering a value in the Wait field, and check the box next to that field if you want Windows 7 to display the login screen after interrupting the screensaver.
You can modify some built-in screensaver options, such as 3D Text and Photos, by clicking on the Settings button. For 3D Text, choose what text is displayed by typing it in the Custom Text field, select the desired rotation type, surface style and resolution, and click OK to confirm the changes. For custom screensavers, double-click on the downloaded screensaver if it’s an executable file, or right-click on it, and select the Install option if it’s an SCR file.