JP:

Sorry for the demo fiasco, I feel your pain.

Even though I have no hands on experience with Windows 7 yet, I have worked with SQL Express a bit.  First, I don't know if you are familiar with the idea of the "User Instances" introduced in SQLX 2005.  Read about it here: http://msdn.microsoft.com/en-us/libra....  Look for the topic "User Instances".  I never liked that concept, even on my laptop, when I'm doing development or a critical demo, I rather have a true instance of SQL Server, in that way the database is there when I need it, file attached, memory resources allocated, etc.  The connection with the "User Instance" database file is too loose for my taste and I think it incurs additional overhead I don't care about.

The other thing is that after doing The Google about the subject I found this article: http://support.microsoft.com/kb/2002980.  Don't know if it is your problem exactly but it certainly looks suspicious. 

In any case, I would recommend you try the setup with a real SQL instance with the attached database.  There is an article somewhere on how to move the User Instance DB to a regular SQL Server attached DB.  You then use a connection string like you would to a SQL Server that is located on a separate box on the network somewhere.  By the way, make sure that your connection string does not have the parameter for the protocol (in the default configuration not all protocols are enabled but for connectivity inside of your PC only "Shared Memory" is sufficient and the fastest anyway).

Hope this helps.

Carlos

None of these issues seem to have anything to do with DNN itself, but your connection to SQL Express.  Since I have a number of DNN installs working with SQL Express, on Windows 7, Server 2008, etc., and none of them gave me any trouble setting them up, I have to assume it's your installation and/or configuration of SQL: Express at issue.  If you are having troubles with SQL Express, the SQL logs and the Windows event logs should give you some help.  You  might also try some of the SQL forums for help.  If it helps, almost every SQL Express issue I see comes from either User Instances or using Windows Authentication, especially when someone moves or attaches a database.

Jeff