error: Cannot autolaunch D-Bus without X11 $DISPLAY

I urgently need to reset Compiz to its default settings because my desktop doesn't show the Dash or menu bar.

When I type:

dconf reset -f /org/compiz/

It says:

error: Cannot autolaunch D-Bus without X11 $DISPLAY

Usage:
  dconf reset [-f] PATH

Reset a key or a dir. -f is required for dirs.

Arguments:
   PATH          Either a KEY or DIR
   KEY           A key path (starting, but not ending with '/')
   DIR           A directory path (starting and ending with '/')

What to do next?

Best regards

Solution 1:

export DISPLAY=:0.0

if you see

Xlib: connection to ":0.0" refused by server
Xlib: No protocol specified

Error: Can't open display: :0.0

then

xhost +