You can run screensaver on your system with a single click, If you have any screensaver file like .scr extension, or first download it using Internet, there are many free sites for screensaver downloading.
If you have not any .scr file then please go to Start button, and click on Search button. Here in search windows type *.scr and search all screen saver file from your hard disk.
Here you will find a list of screensavers in the results. Pick a screensaver you want. You can preview it by double-clicking it.
Right click on the file, choose Send To, and then click Desktop (create shortcut).
To activate the screensaver, double-click the icon on your desktop