Login error messages

Hello, i am trying to find how i can change the error message “ERROR: Invalid username. Lost your password?” that appears in Login page (My Account) when someone enters wrong username/password. I would like to change the text and remove the “lost your password?” link.
I would also like to find and translate the messages “ERROR: The password field is empty.” and “ERROR: The username field is empty.” that appear when someone uses the Login Widget and leaves an empty field. I used the CodeStyling Localization plugin but i can’t find any of them. Any ideas please?

http://wordpress.org/extend/plugins/woocommerce/