'MediaType 12 is for "fixed hard disk media".  Full list of that and other WMI / WQLable stuff here:
        'http://msdn.microsoft.com/en-us/library/aa394173(VS.85).aspx

        Dim query As New System.Management.WqlObjectQuery("select * from Win32_LogicalDisk where MediaType = 12")
        For Each holdObject As System.Management.ManagementObject In New System.Management.ManagementObjectSearcher(query).Get()
            Console.WriteLine(String.Format("Drive: {0} - Volume Serial ID: {1}", holdObject("DeviceID"), holdObject("VolumeSerialNumber")))
        Next

Private Declare Function GetVolumeInformation Lib _
   "kernel32.dll" Alias "GetVolumeInformationA" _
   (ByVal lpRootPathName As String, _
   ByVal lpVolumeNameBuffer As String, _
   ByVal nVolumeNameSize As Integer, _
   lpVolumeSerialNumber As Long, _
   lpMaximumComponentLength As Long, _
   lpFileSystemFlags As Long, _
   ByVal lpFileSystemNameBuffer As String, _
   ByVal nFileSystemNameSize As Long) As Long

Public Function DriveSerialNumber(ByVal Drive As String) As Long
    
    'usage: SN = DriveSerialNumber("C:")
 
    Dim lAns As Long
    Dim lRet As Long
    Dim sVolumeName As String, sDriveType As String
    Dim sDrive As String

    'Deal with one and two character input values
    sDrive = Drive
    If Len(sDrive) = 1 Then
        sDrive = sDrive & ":"
    ElseIf Len(sDrive) = 2 And Right(sDrive, 1) = ":" Then
        sDrive = sDrive & ""
    End If
  
    sVolumeName = String$(255, Chr$(0))
    sDriveType = String$(255, Chr$(0))
    
    lRet = GetVolumeInformation(sDrive, sVolumeName, _
    255, lAns, 0, 0, sDriveType, 255)

    DriveSerialNumber = lAns
End Function

Private Sub Command1_Click()
    MsgBox DriveSerialNumber(Drive1.Drive)
End Sub