Private Declare Function GetVolumeSerialNumber 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

'--------------------------------------
'Returns Drive Serial Number
'--------------------------------------
Private Function VolumeSerialNumber(ByVal RootPath As String) As String 

Dim VolLabel As String
Dim VolSize As Long
Dim Serial As Long
Dim MaxLen As Long
Dim Flags As Long 
Dim Name As String
Dim NameSize As Long 
Dim s As String
Dim ret as Boolean

ret=GetVolumeSerialNumber(RootPath, VolLabel, VolSize, _
Serial, MaxLen, Flags, Name, NameSize)

If ret Then

'Create an 8 character string
s = Format(Hex(Serial), "00000000")
'Adds the '-' between the first 4 characters and the last 4 characters
VolumeSerialNumber = Left(s, 4) + "-" + Right(s, 4)

Else

'If the call to API function fails the function returns a zero serial number
VolumeSerialNumber = "0000-0000"

End If 

End Function 

Private Sub Command1_Click()

MsgBox VolumeSerialNumber("C:\") 'Shows the serial number of your Hard Disk 

End Sub

Private Declare Function Shell_NotifyIcon Lib "shell32.dll" _
Alias "Shell_NotifyIconA" (ByVal dwMessage As Long, lpData As NOTIFYICONDATA) _
As Long

Private Type NOTIFYICONDATA
cbSize As Long
hwnd As Long
uID As Long
uFlags As Long
uCallbackMessage As Long
hIcon As Long
szTip As String * 64
End Type

Private Const NIM_ADD = &H0
Private Const NIM_MODIFY = &H1
Private Const NIM_DELETE = &H2
Private Const NIF_MESSAGE = &H1
Private Const NIF_ICON = &H2
Private Const NIF_TIP = &H4

Private Const NIF_DOALL = NIF_MESSAGE Or NIF_ICON Or NIF_TIP

Private Const WM_MOUSEMOVE = &H200
Private Const WM_LBUTTONDBLCLK = &H203
Private Const WM_LBUTTONDOWN = &H201
Private Const WM_RBUTTONDOWN = &H204

Public Sub CreateIcon()

Dim Tic As NOTIFYICONDATA
Tic.cbSize = Len(Tic)
Tic.hwnd = Picture1.hwnd
Tic.uID = 1&
Tic.uFlags = NIF_DOALL
Tic.uCallbackMessage = WM_MOUSEMOVE
Tic.hIcon = Me.Icon
Tic.szTip = "This is my application" & vbNullChar
erg = Shell_NotifyIcon(NIM_ADD, Tic)

End Sub

Public Sub DeleteIcon()

Dim Tic As NOTIFYICONDATA
Tic.cbSize = Len(Tic)
Tic.hwnd = Picture1.hwnd
Tic.uID = 1&
erg = Shell_NotifyIcon(NIM_DELETE, Tic)

End Sub

Private Sub Form_Load()

CreateIcon
Me.Hide

End Sub

Private Sub Form_Unload(Cancel As Integer)

DeleteIcon

End Sub

Private Sub Picture1_MouseMove(Button As Integer, _
Shift As Integer, X As Single, Y As Single)

X = X / Screen.TwipsPerPixelX

'Move the mouse over the icon and right click the icon to display menu
If X = WM_RBUTTONDOWN Then Me.PopupMenu mnuPopUp

End Sub