Cambiar contraseña de ROOT en MySQL 5

1. Login as root to the box with the MySQL server.
2. Stop MySQL server.
3. Open the mysql server startup script. This is the file you have just executed to stop MySQL server.
4. Find the line that contains the mysqld_safe command and add --skip-grant-tables as its parameter.
5. Start MySQL server.
6. Login as the mysql user and connect to the mysql user/permission database and run the update queries:
   # mysql -u root mysql
   mysql> UPDATE user SET Password=PASSWORD('newrootpassword') WHERE User='root';
   mysql> FLUSH PRIVILEGES;
   replacing newrootpassword with the new root password to the box with the MySQL server.
7. Exit mysql database by typing \q.
8. Exit mysql user console by typing exit
9. Stop MySQL server.
10. Open the mysql server startup script and remove the --skip-grant-tables parameter you added above.
11. Start MySQL server.
12. Open file ~mysql/.my.cnf and update the password in the corresponding line.