Изменить RootKey для TRegIniFile

uses Registry;

procedure TForm1.Button1Click(Sender: TObject);
var
  WinIni: TRegIniFile;
begin
  WinIni := TRegIniFile.Create('');
  WinIni.RootKey := HKEY_LOCAL_MACHINE;
  WinIni.WriteString('Frank', 'Borland', 'Writes Fast Code!');
  WinIni.Free;
end;