help with log on mysql !!

[duc le]

HI !! i wish someone could help me out of this

after installed everything (mysql, IIS, php)

i use command prompt . and go to mysql/bin

i created root password by thic command : mysqladmin -u root password 'hello'
and then i log on mysql : mysql -u root -p
and enter the password that i have created 'hello'

and it dis play the error message

Access denied for user 'root@localhost'

can someone help me out plssssss....thankz