procedure RegKeyList(const ARootKey: Windows.HKEY; const ASubKey: string;
  const AKeyList: Classes.TStrings);
begin
  with Registry.TRegistry.Create do
    try
      RootKey := ARootKey;
      if OpenKeyReadOnly(ASubKey) then
        GetKeyNames(AKeyList)
      else
        AKeyList.Clear;
    finally
      Free;
    end;
end;
//delphi/2293