I need your help in order to get out of a mess I've got in. After installing successfully Ubuntu 13.10, I wanted to install some missing codecs in order to open mp3 and mp4 files. I found the solution in a website page which as well was explaining how to change the desktop interface installing gnome desktop. I should have never done it. I have neither experience nor skills in dealing with operative systems.
I entered this command line:
sudo apt-get install gnome-shell ubuntu-gnome-desktop
consequently, the background changed to black (dark grey) and icons disappeared.
I have no clues about how to get rid of this gnome and restore Unity which served me so well in at least three happy years of using Ubuntu without issues.
Sorry for my broken English.
I hope you could help me, and I beg you not to scold me too much for my imprudence.
Thanks a lot