You can also check to see if they can run the application and if so run the application using the users credentials by doing some like the following:

        <STAThread()> _
        Public Shared Sub Main()
            Try
                ' Assign current windows user to thread that runs the application
                AppDomain.CurrentDomain.SetPrincipalPolicy _
                (System.Security.Principal.PrincipalPolicy.WindowsPrincipal)

                ' Verify current user membership in windows authentication
                ' security groups
                If System.Threading.Thread.CurrentPrincipal.Identity.IsAuthenticated Then
                    If System.Threading.Thread.CurrentPrincipal.IsInRole("YOUR.COM\YourAppUsers") _
                    Or System.Threading.Thread.CurrentPrincipal.IsInRole("YOUR.COM\YourAppUsers") Then
                        Try

                            ' Instantiate the main application form
                            If result = DialogResult.OK Then
                                Application.Run(New MainForm)
                            End If

                        Catch e As Exception
                            ' Write the error to the application log
                            Something.Log.WriteException(e)

                            ' Display the Exception form
                            Dim ExceptForm As New mmExceptionForm(e.Message, e.StackTrace)
                            ExceptForm.ShowDialog()
                        Finally
                        End Try
                    End If
                End If...