HOW to get the Hard Disk Serial number

[piscis]

Does anyone knows why this code is not working?

Public Class Form1
 
    Private Declare Function GetVolumeInformation Lib "kernel32" Alias "GetVolumeInformationA" (ByVal lpRootPathName As String, ByVal lpVolumeNameBuffer As String, ByVal nVolumeNameSize As Long, lpVolumeSerialNumber As Long, lpMaximumComponentLength As Long, lpFileSystemFlags As Long, ByVal lpFileSystemNameBuffer As String, ByVal nFileSystemNameSize As Long) As Long
 
 
    Public Function GetSerial(ByVal str As String) As Long
        Dim Buf$, Name$, Flags&, Length&
        Dim Serial As Long
        GetVolumeInformation(str, Buf$, 255, Serial, Length, Flags, Name$, 255)
        GetSerial = Serial
    End Function
 
    Private Sub Form_Load()
        Label1.Text = CStr(GetSerial("C:\"))
        'This prints the hard drive serial number of C: here. No other drive Is needed
    End Sub
 
End Class