Windows Mail itself does not have a username or password.
However, if you set up a mail account in Windows Mail, the
mail server you are accessing via Windows Mail will require a
username and password. If you have forgotten them, the only
way to retrieve that information is to contact your mail service
provider.
If the account in question is for the domain golfsmitheurope.eu,
you would have to contact the hosting service, Telivo: http://www.telivo.com/contact.html