SQL Server: удалить пользователя

Я пытаюсь написать запрос на удаление регистрации пользователя из моей базы данных SQL Server, но когда я пытаюсь удалить пользователя, я получаю эту ошибку:

System.InvalidOperationException: 'ExecuteReader: Connection property has not been initialized.'

Мой код:

Public Class DeleteForm
Private Sub btnDelete_Click(sender As Object, e As EventArgs) Handles btnDelete.Click
    Dim conn = New SqlConnection("Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=dbProject;Integrated Security=True")

    Using cmd = New SqlCommand("SELECT * FROM tblLogin WHERE username = " & txtUsername.Text, conn)
        conn.Open()
        Dim reader As SqlClient.SqlDataReader = cmd.ExecuteReader

        If reader.Read = True Then
            If txtUserPass.Text = txtCheckPass.Text Then
                Dim deleteOk As Integer = MessageBox.Show("This cant be undone!" & vbCrLf & "Are you sure?", "Warning!", MessageBoxButtons.YesNo, MessageBoxIcon.Warning)
                If deleteOk = DialogResult.Yes Then
                    Dim queryDelete As String = "DELETE FROM tblLogin WHERE username = " & txtUsername.Text & " and password = " & txtPassword.Text
                    Dim cmdDelete As New SqlClient.SqlCommand(queryDelete, conn)

                    If conn.State = ConnectionState.Closed Then conn.Open()
                    reader.Close()
                    cmdDelete.ExecuteNonQuery()
                    MsgBox("Cancellazione eseguita correttamente!")
                    cmdDelete.Dispose()
                    conn.Close()
                ElseIf deleteOk = DialogResult.No Then

                End If
            Else
                MsgBox("The passwords arent matching!")
            End If
        Else
            MsgBox("User not found")
            conn.Close()
            txtUsername.Clear()
            txtUsername.Focus()
            txtUserPass.Clear()
            txtCheckPass.Clear()
        End If
    End Using
  End Sub
End Class