This being the newbie forum, one knows not what the OP knows or means, exactly. So let him/her respond so we can help them better.
Regarding your bonnie point, Soadyheid, you are correct that Ubuntu defaults to no root user ... something that has always annoyed me about the distro.
from your user account after setting up a new machine, that new password applies to the root user, and a root user is enabled.
The OP said he was trying to change a user password, but he also did not say he was locked out of his machine,
and then in his example he implied that he was already root, so it's really unclear what problem we are trying to fix!
Throwing several options at him is a good strategy. Your post about a workaround on grub for someone who IS locked out is very interesting,
and could certainly be useful!
Going back to the OP
root@user-aspire-m3420:~# -d, --delete
The above snippet of code makes no sense because -d is an "option" but there is no command. Not sure where you got it or what you mean.
Do you understand the basic linux command structure? (Let us know if not).
Perhaps you meant to type:
That WOULD disable the password for the root user. If you mean to disable your own password, and you are joecool, then you
root@user-aspire-m3420:~#passwd -d joecool
This assumes that you HAD enabled root, and that you already were root.
Do feel free to enlighten us about what you know, what accounts exist on your machine and what you are really trying to do.