You say you tried both Window and SQL authorisation. The question is whether you are sure this error message appeared when you attempted the *SQL* login - as Sergey pointed out this error is specific to a Windows login attempt.....

>Yes, I'm sure
>
>>Are you sure? I've seen this error with Windows Auth only.
>>
>>>I have tried both Windows Auth and SQL Auth.
>>>
>>>>What type of authentication are you using in this case?
>>>>
>>>>>I have SQL 2005 running on Win 2003 Server box. I have a Win 7 Pro box that can connect to the server just fine. My laptop running XP Pro also connects fine. I just bought another PC running Win 7 Home Premium. I put SSMS on it and when I try to connect to the server I get:
>>>>>
>>>>>

>>>>>Login failed for user ''. The user is not associated with a trusted SQL Server connection. (.Net SqlClient Data Provider)
>>>>>

>>>>>
>>>>>One thing to note: I have only been able to connect to SQL from my older PC and my laptop via the IP address. There's an issue with my domain controller on the server. I'm working on it, but like I said, I have been able to connect to SQL via IP.