Option Explicit
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" _
(ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function SendMessageA Lib "user32" _
(ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Integer, _
ByVal lParam As Long) As Long
Private Declare Function ExtractIconA Lib "shell32.dll" _
(ByVal hInst As Long, ByVal lpszExeFileName As String, ByVal nIconIndex As Long) As Long
Private Sub UserForm_Initialize()
Dim Fichier As String
Dim x As Long
'Chemin et nom du fichier icône à afficher
Fichier = "C:\Documents and Settings\mimi\dossier\bouton.ICO"
'Vérifie si le fichier existe
If Dir(Fichier) = "" Then Exit Sub
x = ExtractIconA(0, Fichier, 0)
SendMessageA FindWindow(vbNullString, Me.Caption), &H80, False, x
End Sub