cannot connect/login error message

I am trying to connect to a virtual directory where there is an application
that was developed in .asp.net - it is linked to a sql server database. I am
using IIS, Server 2003 and SQL Server 2000 - same server - Any ideas where
this may be coming from? I posted this message under connect and security
sections. Thanks.
Server Error in '/Admin' Application.
Login failed for user 'NT AUTHORITY\NETWORK SERVICE'.
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: Login failed for user
'NT AUTHORITY\NETWORK SERVICE'.
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: Login failed for user 'NT AUTHORITY\NETWORK SERVICE'.]
System.Data.SqlClient.ConnectionPool.GetConnection (Boolean&
isInTransaction) +474
System.Data.SqlClient.SqlConnectionPoolManager.Get PooledConnection(SqlConnectionString options, Boolean& isInTransaction) +372
System.Data.SqlClient.SqlConnection.Open() +384
ut.hfrp.asap.DAO.BaseDAO.getConnection() +83
[DAOException: Unable to create connection to database]
ut.hfrp.asap.DAO.BaseDAO.getConnection() +154
ut.hfrp.asap.DAO.UserDAO.GetList() +70
ut.hfrp.asap.BusObj.Settings.AirlineSettings.GetUs erList() +30
ut.hfrp.asap.ManagerApp.Login.SubmitLogin_Click(Ob ject sender, EventArgs
e) +51
System.Web.UI.WebControls.Button.OnClick(EventArgs e) +108
System.Web.UI.WebControls.Button.System.Web.UI.IPo stBackEventHandler.RaisePostBackEvent(String eventArgument) +57
System.Web.UI.Page.RaisePostBackEvent(IPostBackEve ntHandler
sourceControl, String eventArgument) +18
System.Web.UI.Page.RaisePostBackEvent(NameValueCol lection postData) +33
System.Web.UI.Page.ProcessRequestMain() +1292
LizW
The ASP service Account is running under Networkservice Account which
is not priviledged in the SQL Server database. Either you change the
authentication in your application to SQL Server authentication
(Checkout the connectionstrings on www.connectionstrings.com for that)
or you change the service account of ASP to a domain or local account
which has to be priviledged in SQL Server.
HTH, Jens Suessmeyer.