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\CurrentVersion\Authentication\ LogonUI\Background
3. Double-click the OEMBackground DWORD key
4. Set value of the key to 1.

5. Select a background image for Logon Screen with size less than 256KB in size (Use of Image Resize software like VSO Resizer can help)
6. Copy that image into the following folder
7. Rename the image to backgroundDefault.jpg
8. Reboot, and now your logon Image would have changed.
1. Go to start, and click on Run, type Regedit & press enter there.
2. Navigate to : HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Authentication\ LogonUI\Background
3. Double-click the OEMBackground DWORD key
4. Set value of the key to 1.
5. Select a background image for Logon Screen with size less than 256KB in size (Use of Image Resize software like VSO Resizer can help)
6. Copy that image into the following folder
C:\Windows\system32\oobe\info\backgrounds
7. Rename the image to backgroundDefault.jpg
8. Reboot, and now your logon Image would have changed.
Nice Tutorial but how what if I want more customization options such as change of loading bar etc?