How to Change Logon Background in Windows-7

1. Open the Windows Start menu and enter regedit into the search bar.

2. Expand HKEY_LOCAL_MACHINE.

3. Expand SOFTWARE.

4. Expand Microsoft.

5. Expand Windows.

6. Expand CurrentVersion.

7. Expand Authentication.

8. Expand LogonUI.

9. There should be a folder named Background.

10. You should be here :  HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Authentication\LogonUI\Background

11. Click on Background folder. There should be a key named OEMBackground. If it doesn't exist add a new DWORD value with the name OEMBackground.

12. Double click on the entry OEMBackground, and change the value from 0 to 1.

13. Press Windows+R keys simultaneously to open the Run.

14. Type %windir%\system32\oobe in Run.

15. Create a new folder named info, and open it.

16. Create a new folder within info named backgrounds.

17. Rename your desired wallpaper as backgroundDefault and place it inside the folder backgrounds.

Note : Images must be less than 245KB in size.

18. Done! Now Log Off or Reboot your PC to see the changes.