para um teste coloque o seu icone em um picture box, depois cole este código
Private Declare Function SendMessage Lib _
"user32" Alias "SendMessageA" (ByVal _
hWnd As Long, ByVal wMsg As Long, _
ByVal wParam As Long, lParam As Any) _
As Long
Private Declare Function ReleaseCapture Lib _
"user32" () As Long
Private Sub Picture1_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
Dim rec&
If Button And 1 Then
ReleaseCapture
rec& = SendMessage(Picture1.hWnd, &HA1, 2, 0&)
End If
End Sub
pronto veja se era isto