I have finally made the switch from Windows to Ubuntu and now have to ask the first question because search did not help me this time.
The problem is easily described: The elements shown in the lockscreen on boot (ubuntu logo in the middle and watermark in bottom left corner) stay there even when I'm entering desktop and I cannot change the wallpaper anymore.
How can I remove them again? They haven't been there in the first place, but after updating Ubuntu with Update Center, the problem occured.
As I cant post an image here with my reputation, pls see this link: http://s30.postimg.org/age8fraww/Screenshot_from_2014_05_30_23_27_58.jpg
Thanks for your help and time.