THANKS FOR YOUR HELP IN ADVANCE.I'm trying to install 6.2.3 and cannot access the TABLES/VIEWS/PROCEDURES clicks for the contents of the DATABASE.MDF file.I get an ERROR when I try to access their contents. I also get the error "Unable to cast object of type 'System.DBNull' to type 'System.String.' I was using SSMS to ATTACH & DETACH the DNN Database.mdf file, but, unknowingly, I had several 'connections' open and deleted them all at one.I've deinstalled and reinstalled SQL SERVER 2008 without success, thinking that I had a "default instance" problem which was preventing SQL from talking to the database.I've also made sure that NETWORK SERVICE, among others, is opened "full blast", so I shouldn't be having a security problem.With all this work, I'm still not able to access the Database.mdf file within DNN.HELP, PLEASE !!!!Jeff

Sebastian, THANK YOU SO MUCH FOR YOUR HELP.I should've said earlier: I'm a newbie. Your words about the app pool, as intelligent as they are, went right over my head.I'm trying to work right now with the existing database, thinking (hoping) that it's some sort of 1) SECURITY or 2) SQL problem.I appreciate all of your words of help; any directed along those two lines will be appreciated even more.Jeff

The only apppool active is "ASP.NETv4.0, Started, v4.0 (.NET FRAMEWORK), Integrated (Managed Pipeline), ApplicationPoolIdentity (Identity), 1 (Applications)."Jeff