To install a winter desktop background on a computer, open the desktop background, click the picture that you want to use and crop the picture if necessary, and save it as the desktop background. Users can also download good winter desktop pictures online.

Open the desktop background by clicking the Start button and then Control Panel. Alternatively, you can access it by typing "desktop background" in the search box. Choose any picture that you want, or you can download one and then double-click it to become the desktop background. You can either crop it to fill or set it to fit the screen and then save the changes.