If everything else is set up right ,your web.config(open in notepad and edit these lines) for 2005 express should be uncommited and 2000/2005 should be commited out.
<!-- Connection String for SQL Server 2005 Express ->
<add
name="SiteSqlServer"
connectionString="Data Source=.\SQLExpress;Database=your database;User ID=your user ID;Password=your password;Integrated Security=True;User Instance=True;AttachDBFilename=|DataDirectory|Database.mdf;"
providerName="System.Data.SqlClient" />-->
Delete the commit out arrows and type by hand the database info highlighted. Once your done do the same for the "<appSettings>".
Final result will look like this:
<connectionStrings>
<!-- Connection String for SQL Server 2005 Express -->
<add name="SiteSqlServer" connectionString="Data Source=workstation\SQLExpress;Database=your database;user ID=Your user id;Password=your password;Integrated Security=True;User Instance=True;AttachDBFilename=|DataDirectory|Database.mdf;" providerName="System.Data.SqlClient"/>
<!-- Connection String for SQL Server 2000/2005
<add
name="SiteSqlServer"
connectionString="Server=(local);Database=DotNetNuke;uid=;pwd=;"
providerName="System.Data.SqlClient" />
-->
</connectionStrings>
<appSettings>
<!-- Connection String for SQL Server 2005 Express - kept for backwards compatability - legacy modules -->
<add key="SiteSqlServer" value="Data Source=workstation\SQLExpress;Database=your database;User ID=your user id;Password=your password;Integrated Security=True;User Instance=True;AttachDBFilename=|DataDirectory|Database.mdf;"/>
<!-- Connection String for SQL Server 2000/2005 - kept for backwards compatability - legacy modules
<add key="SiteSqlServer" value="Server=(local);Database=DotNetNuke;uid=;pwd=;"/>
-->
So add in your your name ,your database, and your password in the highlight areas and commit out the connection strings around the connection string for both sql 2000/2005 settings. Remember not to copy and paste because you could get white space in the code and it will result in an error. Good luck!