New Installation - Can Not Connet to Server On My PC

I have just installed SQL Express and Server Management Studio on my PC. I also have IIS 5.0 on WinXP. When I open Management Studio and try to connect the sI get the following error message:- Login failed for user '(null)'. Reason: Not associated with a trusted SQL Server connection. (.Net SqlClient Data Provider) .

This happens if I change the server, change the authentication method or try my user name or the 'sa ' user. To make things even more frustrating I did the same installation on my laptop earlier this year with no problems.

Has anyone any answers to my problem?

Thanks

hi,

having modified the authentication property (and restarted the service), did you enable the sa login?.. verify in the Instance->Security->Logins->sa Properties (Status tab) the login is enabled..

regards