Cannot connect to database on windows 2003 server

am setting up a server to run my site.  I am running on Wndows 2003 and have SQL Server Express 2008 installed.  I am running the web site on IIS.  I am getting an error when I try to access the database when I try to "register a user":  Also, I changed the database to not be read only, but I am still gettng the error.  I cannot change the folder APP_DATA from being read only (it is a grey mark) but that should not matter since the mdf file can be read.

The error and stack trace are:

Failed to update database "C:\INETPUB\WWWROOT\TEST\APP_DATA\ASPNETDB.MDF" because the database is read-only.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Data.SqlClient.SqlException: Failed to update database "C:\INETPUB\WWWROOT\TEST\APP_DATA\ASPNETDB.MDF" because the database is read-only.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.  

Stack Trace:


[SqlException (0x80131904): Failed to update database "C:\INETPUB\WWWROOT\SIGH\APP_DATA\ASPNETDB.MDF" because the database is read-only.]
   System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection) +1950890
   System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) +4846875
   System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) +194
   System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) +2392
   System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString) +204
   System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async) +954
   System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result) +162
   System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe) +175
   System.Data.SqlClient.SqlCommand.ExecuteNonQuery() +137
   System.Web.Security.SqlMembershipProvider.CreateUser(String username, String password, String email, String passwordQuestion, String passwordAnswer, Boolean isApproved, Object providerUserKey, MembershipCreateStatus& status) +2430
   System.Web.UI.WebControls.CreateUserWizard.AttemptCreateUser() +318
   System.Web.UI.WebControls.CreateUserWizard.OnNextButtonClick(WizardNavigationEventArgs e) +102
   System.Web.UI.WebControls.Wizard.OnBubbleEvent(Object source, EventArgs e) +418
   System.Web.UI.WebControls.CreateUserWizard.OnBubbleEvent(Object source, EventArgs e) +161
   System.Web.UI.WebControls.WizardChildTable.OnBubbleEvent(Object source, EventArgs args) +19
   System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +37
   System.Web.UI.WebControls.Button.OnCommand(CommandEventArgs e) +118
   System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +166
   System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1565