How to enable ROOT password in Ubuntu 12.0.4

1. Open a terminal

2. Type sudo passwd -u root

(This is enable root account password expiry time)

3. Type passwd root

(This command is for changing the ROOT password)

4. Please enter the password as required by you

5. Again enter the password as the same entered first time.

6. Type su

(Now it would ask for ROOT password give your password and enter into ROOT.