Just Follow this steps:
- Go to Run (PRESS Windows logo + R)
- Type Regedit
- the locate this: HKCU/Control Panel\Desktop had a Value called 'Wallpaper'
- Right Click Wallpaper and Click Modify
- and Copy this '%windir%\web\wallpaper\windows\img0.jpg' (without quotes)
If not working try this software called RemoveWat
RemoveWat is a tool that use to Remove Watermarks like this picture below:
RemoveWAT 2.2.6
Just download it, run as admin and there you go. Your system will reboot for the program to take effect.