After a few minutes of inactivity, your computer usually shows a Windows logo or stars moving across the screen. These are screen savers and you don't have to keep the one that starts automatically. You can have some fun by changing the screen saver.
To change the Screen Saver in Windows XP, just right-click on any empty portion of the computer Desktop and choose Properties. If you are using Vista, do the same thing; only choose Personalize from the drop-down menu.
Then click on the Screen Saver tab. Click on the down-arrow in the Screen Saver box. Choose the Screen Saver you would like. You can click on the Preview button to see what it will look like. After you find one you like, click on the OK button. On the same screen, you can also change the amount of time that elapses before the Screen Saver starts. This will be the amount of time from the last key press or the last mouse movement and the start of the Screen Saver.
You can also put your own words on the screen to use as a screen saver. Check out the Screen Saver choice called "Marquee", then choose a color and type in the words. Have your screen saver say "Happy Birthday" or anything else you like.
If you use Windows Vista, be sure to check out the new screen savers that come with Vista. From the Screen Saver drop down list, choose Ribbons (shown above) or my favorite, Bubbles.