I have met this problem many times before, and here is how a cleared the way into my wishes:
rm -f ~/.ICEauthority && rm -fr ~/.cache/*
then zap X to avoid further temporary files, press: "Ctl+Alt+Backspace" (if this doesn't work then Logout without saving the session
or if you can't manage to avoid save session press Ctl+Atl+Del to reboot, or issue command as root
Login again as regular user.
Hope that helps.