mysqld --skip-grant-tables

UPDATE user SET password=PASSWORD('password') WHERE user ='root';

mysqladmin shutdown

mysql --version  команда выдает следующее
mysql  Ver 15.1 Distrib 10.1.9-MariaDB, for Win32 (AMD64)

mysqld_safe --skip-grant-tables

mysql --user=root mysql

update user set Password=PASSWORD('new-password') where user='root';
flush privileges;
exit;

mysql 5.7

mysql --user=root mysql
update user set authentication_string=PASSWORD("new_password") where User='root';
flush privileges;
exit;