User1154043639 posted
In the blogengine.net login page you can use Iframe to windows login authentication. You can keep a list of usernames in your database which contain only the usename (password is same as the username) So once you get a valid windows live user you can call
Memebership.ValidateUser(UserId, UserId); create the autentication cookie.
Please refer this article for more information
However in MSDN says
The default provider stores membership information in a Microsoft SQL Server database. However, you can use other providers as well, such as a provider for
Windows Live ID
Reference, which is the ideal case. Please do have a look at it as well.