Visual Basic

Imports System
Imports System.Management

Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        TextBox1.Text = GetHddSerial()
    End Sub

    Public Function GetHddSerial() As String
        Dim query As New SelectQuery("Win32_PhysicalMedia")
        Dim search As New ManagementObjectSearcher(query)
        Dim info As ManagementObject
        Dim strSerial As String = ""
        Dim i As Integer
        For Each info In search.Get
            strSerial &= info("SerialNumber").ToString
            i += 1
            If i = 1 Then Exit For
        Next
        Return Trim(strSerial)
    End Function
End Class