Got Active Directory Working - How do I remove default provi

I followed the instructions in Windows-Authentication.rar which I downloaded from http://www.sitefinity.com/devnet/forums/sitefinity-4-x/general-discussions/active-directory-and-permissions.aspx

Upon completing the instructions, I was able to assign permission to Active Directory  users in Sitefinity and the users could log in.

However, when going to the login screen users are presented with a dropdown containing 3 Authentication providers:

1. LDapUsers
2. Default
3. The domain name I specified in step 3 of the Windows-Authentication.rar document.

Questions
1. How do I make it so the users are not presented with any options for selecting an authentication provider, I just want people to login with Active Directory?
2.  The first step in the Windows-Authentication document (downloaded from link at top of this comment) is to enable the LdapUsers provider. I un-enabled it and it disapeared from the dropdown. Is there any reason why it should be enabled?
3. I still need to remove default from the dropdown.

I've slightly revised what I am trying to accomplish. Most of the sites we create are only accessible to employees that have an active directory login. Occasionally we need to give access to non-employees, for those sites I would like the dropdown to appear when a user logs in. However, I don't want the word "default" to appear in the dropdown. What I would like is that the first item in the dropdown be our company name and the second item in the dropdown be the word "Guests". When a user logins by selecting our company name, they will be authenticated by active directory. If the user selects guests than they will be authenticated through sitefinity's own authentication.

Hello,

 If you want to set another membership provider to be the default one, you can do that from Administration >> Settings >> advanced >> Security and there find the DefaultBackendMembershipProvider property and set it with the name of the membership provider that you want to use.
As for changing the name of the Default provider, this wouldn't be possible, because that name is set as a default value for the membership provider and cannot be set otherwise.