Maybe a stupid question, but have you "Joined" the machine to the domain?
If you have just installed the machine, its not automatically joined so it can't log onto it.
Go to Start and type Domain in the search box. One of the options should be "Join a Domain".
You'll need a user with Administrative Privileges in the Domain to join the computer to it.
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Phil AKA Vacunita
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Ignorance is not necessarily Bliss, case in point:
Unknown has caused an Unknown Error on Unknown and must be shutdown to prevent damage to Unknown.