No password set but WD asking for Password

Hello 

 MY WD passport is asking for password while it connected with the pc  … Earlier i have set a password and its being removed .  i tried with that password and its not working and showing me an invalid error message  … I cant format my WD  since it contain some valuble infos …is there any  solution for retrieving mine datas . … i am using in windows  7 and tired in xp  but its not solving mine probelm …Hope  u got mine   question