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

if the problem still exists try to force changing the pass

Stop MySQL Server (on Linux):

/etc/init.d/mysql stop

Stop MySQL Server (on Mac OS X):

mysql.server stop

Start mysqld_safe daemon with --skip-grant-tables

mysqld_safe --skip-grant-tables &
mysql -u root

Setup new MySQL root user password

use mysql;
update user set password=PASSWORD("NEW-ROOT-PASSWORD") where User='root';
flush privileges;
quit;

Stop MySQL Server (on Linux):

/etc/init.d/mysql stop

Stop MySQL Server (on Mac OS X):

mysql.server stop

Start MySQL server service and test to login by root:

mysql -u root -p