Using QGIS 1.8, SQL Server 2012, and OGR 1.9.2 (also fails on our SQL Server 2008 sandbox machine)
When creating a connection in QGIS I'm getting the following errors:
Driver not loaded Driver not loaded
[Microsoft][ODBC SQL Server Driver][DBNETLIB]SQL Server does not exist or access denied. [Microsoft][ODBC SQL Server Driver][DBNETLIB]ConnectionOpen (Connect()). QODBC3: Unable to connect
Here is the DSN connection info I'm using: ( indicates a password, etc.)
Provider=SQLOLEDB.1;Password=;Persist Security Info=True;User ID=;Initial Catalog=;Data Source= \ 
The rest of the connection info I'm getting is correct (ie. username, password, db name, etc.) as per my connection through SQL Server Management Studio and ArcGIS v10.1
Using OGRINFO throws similar errors...I can see MSSQLSpatial in the list of drivers it is trying to use.
I'm having lots of issues with OGR and the MSSQL tools with our development database...
I'm wondering what we might have set wrong in our enterprise environment such that these tools do not communicate with SQL server?
Any thoughts appreciated. Thank you!