You mean Unity.
Well there are a couple of options, I leave the simplest:
You can enter as in previous versions of gnome classic and delete the panel below to only have the main panel and your dock.
Type this in a terminal (Ctrl + Alt + T)
sudo apt-get install gnome-session-fallback
Restart your PC and during the screen really q income next to your username is a picture of nuts, you give click and choose GNOME CLASSIC. Perhaps to install something and you have this option, so I recommend q verify it before.
When you want to enter as it was before GNOME CLASSIC.
When you want to get as far Unity and Unity 2D.
This superfluous saying you can install q q docks you want, but my favorite is AWN hehe.
Luck.