Do check out & heed moderator Kulman's link.

but...

In answer to your question..

If you type 'sudo passwd' in a normal shell (or 'passwd') in a root shell, it *should* accept & update your root password.

However, since all you want to do is mount a drive, 'sudo mount...' should do that without needing to update the root password. Sudo will allow you to do one command as root without needing a password unless this has been changed in recent versions of knoppix.

Having said that, be aware that there are problems writing to ntfs drives from linux and directly writing to your ntfs drive could trash the filesystem on that drive. As far as I know, the only way to safely write to an ntfs partition from linux is to use 'captive ntfs' which you will have to set up on your system before you can use it. I can't tell you how to do this, I don't use it as I have no ntfs partitions.