Okay, thanks, I see now there is no " ! " exclamation in your /etc/passwd: 'root' line.
You may now "Delete" that single post above, that's something personal and security matter: be careful not to post anything like that for your security.
Now we go back to the problem.
When you login as root at runlevel 3 what does it say?
Please post us also the output of "~# dmesg | tail" so that we will know what is happening.
Dont' worry there is always an easy solution to that problem. You can even delete the passwd entry from the /etc/passwd 'root' line so that you can re-enter without password:
Delete whatever lies in-between the two colons " : " e.g.--
so that the two colons will look like contagious:
I have done this with a regular $USER account, but have not yet tried it with ROOT.
Reboot and try to login as root. If you happen to be able to login as root right then and there from the terminal issue command
to change your password to a new one.
And please post back whatever the system spouts out in complaint or error so that we (helpers) are also appraised properly and seek proper solutions. So far WHAT I AM TELLING ARE BASED IN PURE GUESS and assumptions because your feedback is very wanting.