Firefox - Enter username and password for "" at http://localhost - Solution

IIS uses Integrated Authentication and by default IE has the ability to use your windows user account...but don't worry, so does Firefox but you'll have to make a quick configuration change.

1) Open up Firefox and type in about:config as the url

2) In the Filter Type in ntlm

3) Double click "network.automatic-ntlm-auth.trusted-uris" and type in localhost and hit enter

4) Write Thank You To Blogger

As Always, Hope this helped you out.