I have SQL Server 2008 Express and SQL Server 2012 Developer edition installed.
When I want to connect to SQL Server from Visual Studio 2010 I have only option to connect to VISTAUSER-PC/SQLEXPRESS
but I know that the name of 2012 Developer edition is VISTAUSER-PC
so I just write that name, test connection and its working.
DotNetNuke just gives me option to connect to express edition and when I enter VISTAUSER-PC
for the name of the server it cannot connect. I know that DNN works with SQL Server 2012
http://img825.imageshack.us/img825/7582/captureqnn.jpg