I have just moved from Vista to Windows 7 with my development environment and ALL OF A SUDDEN my web app cannot connect to the local SQL Server instance

[DBNETLIB][ConnectionOpen (Connect()).]SQL Server does not exist or access denied.

Funily enough, SQL Management studio express can connect fine. The connection string im using is:

Provider=SQLOLEDB.1;User ID=sa;Initial Catalog=mydatabase;Data Source=.\myinstance;Password=xxx

Does anyone have any idea as to why?


Thanks all for your responses, I fixed the problem by changing the connection string as follows:

Provider=SQLOLEDB.1;Network Library=DBNMPNTW;User ID=sa;Initial Catalog=mydatabase;Data Source=\\.\pipe\MSSQL$myinstance\sql\query;Password=xxx

Try to configure the ALIAS on Microsoft Client Network Configuration.


Check the status of the "Login" that you are using, through SSMS. Also read the error for any error messages.


Perhaps you installed the database instance in Windows Only authentication mode and sa is disabled.

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