CentOS 6.4 : Cannot login as root ssh anymore

CentOS 6.4 : Cannot login as root ssh anymore

When I enter the password it gives me the following error:
login: root
Password: My-password
Login incorrect
I have tried SSH via Putty as well as WinSCP. I get Network Error:
Connection refused.
So what could have gone wrong?
Please advise.
Please Note: root is not the only user on this machine, I can access with
another account and perform some command .
I tried to reset the root password following the instructions on some
other site. All went well, except I get the same error despite changing
the password!
The last major thing I did was : create user , create group , associate
the user to the group created and than change folder dir to the user
inside etc/passwd. After that I start to have the root problem , so i
cancel the user and the group created but i still facing the same problem