Windows 7 is a newly launched Operating System from Microsoft. If you are newly shifted from any other operating system to Windows 7, It'll be difficult for you to understand it until you use it at least a month. As you know it selects log on screen background automatically, and it is impossible for you to change it unless you change some system files.
But changing system files is not that easy task to perform. Here is a small and easy utility with which any one even a kid of 8 years can change the log-on screen background easily and without any difficulty.