What is the primary purpose for a screen saver in Windows?
http://en.wikipedia.org/wiki/Screensaver
The primary purpose of a screen saver in Windows is to prevent the permanent image retention or burn-in on CRT and early generation LCD monitors. In the past, prolonged display of a static image could cause these monitors to have a "ghost" image permanently ingrained on the screen.
However, in modern screens like LED and LCD monitors, burn-in is no longer a significant concern. So the primary purpose of a screen saver has shifted more towards aesthetics or security. A screen saver can include visually pleasing images or animations that activate after a certain period of inactivity, providing an attractive display when the computer is not in use. Additionally, a screen saver can be set to require a password to access the computer again, serving as a security measure to protect your data from unauthorized access when you step away from your computer.