Customize the Windows 7 log-on screen
Windows 7 makes it easy changing the Windows log-on screen.
1. Go to start, and click on Run, type Regedit & press enter there.
2. Navigate to :
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVe
rsion\Authentication\ LogonUI\Background
3. Double-click the OEMBackground DWORD key
4. Set value of the key to 1.
5. Select a background image for Log on Screen with size less than
256KB in size.
6. Copy that image into the
C:\Windows\system32\oobe\info\backgrounds folder (create if doesn't exist)
7. Rename the image to backgroundDefault.jpg
8. Reboot, and now your logon Image would have changed.