16.04 - i can't update my ubuntu

Every time when I enter the commands sudo apt-get update; sudo apt-get upgrade, it shows:

(You might want to run 'apt-get -f install' to correct these.
The following packages have unmet dependencies:
 libpam-systemd : Depends: systemd (= 229-4ubuntu12) but 229-4ubuntu4 is installed
E: Unmet dependencies. Try using -f.)

and after that when i entered sudo apt-get -f install this shows up:

(E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied)
E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?)

What do I do next? I can't update my pc. I also want to install Windows XP alongside.