Desabilitar o botão Fechar do Form

procedure TForm1.FormCreate(Sender: TObject);
var
hwndHandle : THANDLE;
hMenuHandle : HMenu;
begin
hwndHandle := Self.Handle;
if (hwndHandle <> 0) then
begin
hMenuHandle := GetSystemMenu(hwndHandle, FALSE);
if (hMenuHandle <> 0) then
DeleteMenu(hMenuHandle, SC_CLOSE, MF_BYCOMMAND);
end;

end;