Blackground is black, dock is gone, and I can't switch between windows

Macbook retina display 1.5 years old, have El Capitan

I changed my background in system preferences, and my desktop went straight to a black background (a folder stayed there which is still interactive) and my dock disappeared. I try to the do the 4 finger switch between panels and it doesn't work as well. I have tried to turn it off and restart it which did nothing. Although, I am still able to open and close different apps through the spotlight search. I checked the guest account and it has the same issues. I am out of ideas, new help.

thanks