I have a small Windows application in Visual Studio 2010 to which I have an .mdf file connected and this use to work very well. However, recently I installed SQL Server 2008 Management Studio and suddenly I could not open my .mdf file - neither from Visual Studio nor from the applcation. I get the error message 'A network-related or instance-specific error occured while establishing a connection to SQL Server etc.' I have seached google without any solution. Last time I succeded (somehow) to come to a solution by uninstalling SQL Server 2008 and - as I remember - to delete the .ldf file associated to the .mdf file.
As I want to be able to open and modify the .mdf file in my application 'production environment' i.e. not in the Visual Studio development environment, I dared install SQL Server 2008 again and exactly the same happened - the connection to my .mdf file from Visual Studio fails with the same error. Only difference this time is that I am not able to re-establish the connection between the .mdf file and Visual Studio/my application - can you please help?