“The Tweaks.com Logon Changer for Windows 7 provides an easy way to customize the logon screen background with just a few clicks. Simply download the free application, run it and click Change Logon Screen.
The application will prompt for the location of the new background image and then install the new screen behind the scenes. Tweaks.com Logon Changer will even provide a preview of your new background on a logon screen.
When you have settled on a good logon background, click the Test button to see it in action.
If you want the default Windows 7 logon screen back just click Revert to Default Logon Screen and the application will automatically uninstall any customized screens.”
Download Link: Click here