Как сделать кнопку "закрыть" неактивной

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 Declare Function DrawMenuBar Lib "user32" (ByVal hwnd As Long) As Long

Const SC_CLOSE = &HF060
Const MF_BYCOMMAND = &H0


Public Sub DisableXbutton(ByVal frmHwnd As Long)
    Dim hMenu As Long
    hMenu = GetSystemMenu(frmHwnd, 0&)
    If hMenu Then
        Call DeleteMenu(hMenu, SC_CLOSE, MF_BYCOMMAND)
        DrawMenuBar (frmHwnd)
    End If
End Sub

Private Sub Form_Load()
    DisableXbutton (Me.hwnd)
End Sub

SetClassLong(hWnd, GCL_STYLE, GetClassLong(hWnd, GCL_STYLE) | CS_NOCLOSE);