You are not authorized to view this page

You do not have permission to view this directory or page using the credentials that you supplied.

Please try the following:

Contact the Web site administrator if you believe you should be able to view this directory or page.
Click the Refresh button to try again with different credentials.

HTTP Error 401.1 - Unauthorized: Access is denied due to invalid credentials.
Internet Information Services (IIS)

Technical Information (for support personnel)

Go to Microsoft Product Support Services and perform a title search for the words HTTP and 401.
Open IIS Help, which is accessible in IIS Manager (inetmgr), and search for topics titled Authentication, Access Control, and About Custom Error Messages.

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Este erro pode ocorrer quando se alter a senha da conta IUSR_[nome do computador] do Windows.

Se tiver algum site ja instalado que esteja funcionando pode-se pegar a senha deste site utilizando o script adsutil.vbs que se enconta na pasta C:\Inetpub\AdminScripts.

Atente-se que quando tiver o nome W3SVC, isto pode ser o nome do site (ID) que se pode ver no IIS

Fonte:
http://support.microsoft.com/kb/332167
http://blogs.msdn.com/b/vivekkum/archive/2009/02/26/401-1-unauthorized-using-anonymous-access-iusr-account.aspx