Resolve ERROR 1045 (28000): Access denied for user ' root ' @ ' localhost ' (using password:yes) problem

Recently new good MySQL in the MySQL tool to enter, there are always error prompts:
# mysql-u Root-p
Enter Password:
ERROR 1045 (28000): Access denied for user ' root ' @ ' localhost ' (using Password:no)
Or
# mysql-u root-p password ' newpassword '
Enter Password:
Mysqladmin:connect to server at ' localhost ' failed
Error: ' Access denied for user ' root ' localhost ' (using Password:yes) '

Now we've finally found a way out. I was going to reload it now.
The method operation is simple, as follows:
#/etc/init.d/mysql Stop
# Mysqld_safe--user=mysql--skip-grant-tables--skip-networking &
# mysql-u Root MySQL
mysql> UPDATE user SET Password=password (' NewPassword ') where user= ' root ' and host= ' root ' or host= ' localhost '; It's OK to change the blank user password to a non-empty password.
mysql> FLUSH privileges;
Mysql> Quit #/etc/init.d/mysqld restart
# mysql-uroot-p
Enter Password: < Enter the new password newpassword>