"This account is currently not available" ... Please help

[saddafm]

Hello everyone.
To make my system more secure I made a big mistake when changing the root account setting in /etc/passwd file. I changed the root account's shell to /sbin/nologin becase I wanted to login to the root by sudo su. Anyway, after doing that, I logged in by another user account ad then typed sudo su command in order to log in to root via my current account; however, I got this message "This account is currently not available".
Is there anyway to redo what I have done or anyway to access to root account from another user account?

[darkeale]

Hi,

You might be able to fix this by booting from a live CD, mounting the partition where your filesystem is stored and then editing the file from there?

[TrevorH]

Use sudo su -s /bin/bash