I used this command 'sudo passwd -d user' which I thought would just delete my regular users password but now I can't even log in as root. I've tried sudo -i and it doesn't work and I can't use root privileges. Hope someone can help. Thanks
I did find a solution to my problem. I booted into the Grub menu by continually pressing 'shift' when booting up then went to advanced options and loged in to root which didn't require a password. Then I simply changed my password for both sudo and my user by typing 'passwd' for sudo then 'passwd user' for my user and not I have system back to normal.