This video shows you how to change the log on / log in screen on Microsoft Windows 7, as part of the PCWizKid Windows 7 Tips and Tutorial series.
Here's more information on how to change the log on screen on Windows 7:
Try the new Windows Server 2012 for free here http://aka.ms/evaloffer9 Video notes: Navigate in the registry to HKLM\Software\Microsoft\Windows\CurrentVersion\Authentication\LogonUI\Background Then see if there is a DWORD value called OEMBackground and if so set the Hex value to 1. If you do not have OEMBackground then you need to create a new DWORD value key called OEMBackground first. After you are done navigate to c:\windows\system32\oobe\ and create a info folder and then inside it create a backgrounds folder and put a JPEG file in there that is less than 256KB and call the file name backgroundDefault.jpg , then reboot and your done!
NOTE: If you don't have a OEMBackground key, you need to create a new DWord, not a new KEY under ///LoginUI/Background and once created, right-click, choose MODIFY, then set value to 1 as mentioned in video.