Here are the command-line switches available for ASPNET_REGSQL.EXE:

Administrative utility to install and uninstall ASP.NET features on a SQL
server.
Copyright (C) Microsoft Corporation. All rights reserved.

                            -- GENERAL OPTIONS --

-?                Display this help text.

-W                Wizard mode. (Default if no other parameters are specified.)

                         -- SQL CONNECTION OPTIONS --

-S <server>       SQL Server instance (SQL Server 7.0 and above) to work with.

-U <login id>     SQL Server user name to authenticate with; requires -P
                 option.

-P <password>     SQL Server password to authenticate with; requires -U
option.

-E                Authenticate with current Windows credentials.

-C <connection string>
                 Connection string. Instead of specifying a user name,
                 password, and server name, specify a SQL Server connection
                 string. The string must not contain a database name unless
                 otherwise specified.

-sqlexportonly <filename>
                 Generate the SQL script file for adding or removing the
                 specified features and do not carry out the actual
operation.
                 Can be used with the following options: -A, -R, -ssadd, and
                 -ssremove.

                      -- APPLICATION SERVICES OPTIONS --

-A all|m|r|p|c|w  Add support for a feature. Multiple values can be specified
                 together. For example:

                     -A mp
                     -A m -A p

                 all: All features
                 m: Membership
                 r: Role manager
                 p: Profiles
                 c: Personalization
                 w: SQL Web event provider

-R all|m|r|p|c|w  Remove support for a feature. Multiple values can be
                 specified together. For example:

                     -R mp
                     -R m -R p

                 all : All features plus all common tables and stored
                 procedures shared by the features
                 m: Membership
                 r: Role manager
                 p: Profiles
                 c: Personalization
                 w: SQL Web event provider

-d <database>     Database name for use with application services. If no
                 database name is specified, the default database "aspnetdb"
                 is used.

-Q                Quiet mode; do not display confirmation to remove a feature.

          -- SQL CACHE DEPENDENCY OPTIONS (FOR SQL 7.0 AND 2000) --

-d <database>     Database name for use with SQL cache dependency in SQL 7.0
                 and SQL 2000. The database can optionally be specified using
                 the connection string with the -C option instead. (Required)

-ed               Enable a database for SQL cache dependency.

-dd               Disable a database for SQL cache dependency.

-et               Enable a table for SQL cache dependency. Requires -t option.

-dt               Disable a table for SQL cache dependency. Requires -t
option.

-t <table>        Name of the table to enable or disable for SQL cache
                 dependency. Requires -et or -dt option.

-lt               List all tables enabled for SQL cache dependency.

                         -- SESSION STATE OPTIONS --

-ssadd            Add support for SQLServer mode session state.

-ssremove         Remove support for SQLServer mode session state.

-sstype t|p|c     Type of session state support:

                 t: temporary. Session state data is stored in the "tempdb"
                 database. Stored procedures for managing session are
                 installed in the "ASPState" database. Data is not persisted
                 if you restart SQL. (Default)

                 p: persisted. Both session state data and the stored
                 procedures are stored in the "ASPState" database.

                 c: custom. Both session state data and the stored procedures
                 are stored in a custom database. The database name must be
                 specified.

-d <database>     The name of the custom database to use if -sstype is "c".

----------- Note that if you do not have SQLEXPRESS Installed you need to
specify a database and ensure that the web.config file is modified
accordingly.  I generally advise against having SQLEXPRESS user-instances for
configuration of Membership etc. since in a production environment you will
need a normally "attached" database file to the SQL Server and a working
connection string that does *Not* specify a user instance.

--Peter
"Inside every large program, there is a small program trying to get out."
http://www.eggheadcafe.com
http://petesbloggerama.blogspot.com
http://www.blogmetafinder.com

P.S. - at a minimum, to get the Admin app to work, you are going to need
something like this in your web.config to start out:

<connectionStrings>
        <remove name="localSqlServer" />
        <add name="localSqlServer"  
connectionString="server=(local);database=test;uid=youruserid;pwd=yourpassword"  providerName="SqlClient" />
</connectionStrings>

you tried it?  what happened?  have we established that you have an active
database instance running with the aspnetdb DB created?