In Windows XP and Vista, you can configure a screensaver easily:

For XP:
- Click Start, then click Settings and go to Control Panel.
- When the Control Panel window opens, double-click on the Display icon.
- This brings up the Display Properties window.
- Select the Screensaver tab, and select the screensaver you want to use from the drop-down menu.

For Vista:
- Click Start and go to Control Panel. When the Control Panel window opens, double-click on the Personalization icon.
- This brings up the Personalization Properties window.
- Select the Screensaver tab, and select the screensaver you want to use from the drop-down menu.

Next steps for both XP and Vista:
- Determine how many minutes you want the system to be idle before Windows launches the screensaver, and enter that amount of time in the box provided.
- You can click on Preview to see what it will look like in full-screen use. If you want to change the settings, click Settings. Depending on the screensaver, this window can have one or more options that you can modify.
- Once you have finished changing the settings, click OK. You can also use the screensaver for security by checking the "Password protected" box. Click OK again and your screensaver is set to go!