Option Explicit

Private Declare Function FindWindow Lib "user32" Alias _
      "FindWindowA" (ByVal lpClassName As String, ByVal _
      lpWindowName As String) As Long

Private Declare Function GetSystemMenu Lib "user32" (ByVal _
      hwnd As Long, ByVal bRevert As Long) As Long

Private Declare Function DeleteMenu Lib "user32" (ByVal _
      hMenu As Long, ByVal nPosition As Long, ByVal wFlags _
      As Long) As Long

Private Const MF_BYCOMMAND = &H0
Private Const SC_MOVE = &HF010

Private Sub UserForm_Activate()
  Dim hwndForm As Long
  Dim hwndMenu As Long

  hwndForm = FindWindow(vbNullString, Me.Caption)

  If hwndForm <> 0 Then
    hwndMenu = GetSystemMenu(hwndForm, 0)
    If hwndMenu <> 0 Then
      DeleteMenu hwndMenu, SC_MOVE, MF_BYCOMMAND
    End If
  End If
End Sub