service mysqld stop
service mysqld start --skip-grant-tables &
mysql -u root

Access denied for user 'root'@'localhost' (using password: NO)

mysqladmin -u root password 'newpw'

UPDATE mysql.user SET Password=PASSWORD('MyNewPass') WHERE User='root';

ERROR 1142 (42000): UPDATE command denied to user ''@'localhost' for table 'user'

Stop the mysql demon process using this command :

       sudo /etc/init.d/mysql stop

Start the mysqld demon process using the --skip-grant-tables option with this command

       sudo /usr/sbin/mysqld --skip-grant-tables --skip-networking &

start the mysql client process using this command

       mysql -u root

from the mysql prompt execute this command to be able to change any password

       FLUSH PRIVILEGES;

Then reset/update your password

       SET PASSWORD FOR root@'localhost' = PASSWORD('password');

If you have a mysql root account that can connect from everywhere, you should also do:

       UPDATE mysql.user SET Password=PASSWORD('newpwd') WHERE User='root';

Alternate Method:

       USE mysql
       UPDATE user SET Password = PASSWORD('newpwd')
       WHERE Host = 'localhost' AND User = 'root';

And if you have a root account that can access from everywhere:

       USE mysql
       UPDATE user SET Password = PASSWORD('newpwd')
       WHERE Host = '%' AND User = 'root';