if assigned(application.FindComponent('form1')) then
  bla..bla...bla...

var
  i,cnt:integer;
  str:string;
begin
  cnt:=Application.ComponentCount;
  for i:=0 to cnt-1 do
  begin
    if Application.Components[i] is TForm then
    begin
        str:=Application.Components[i].Name;
        ListBox1.Items.Add(str);  // taruh daftarnya di listbox
    end;
  end;
end;

  private
    { Private declarations }
    function GetFormHandle(Index: Integer): TForm;
  public
    { Public declarations }
    propery FormUtama: TForm index 0 read GetFormHandle;
    propery FormInvoice: TForm index 1 read GetFormHandle;
    propery FormReturn: TForm index 2 read GetFormHandle;
    propery FormCetak: TForm index 3 read GetFormHandle;
  end;
implementation
function FindForm(FormName: string): TForm;
var Integer;
begin
  for I:= 0 to Pred(Screen.FormCount) do begin
    Result:= Screen.Forms[I];
    if Result.Name = FormName then 
      Exit;
  end;
  Result:= nil;
end;
function TForm1.GetFormHandle(Index: Integer): TForm;
var AName: string;
begin
  case Index of
  0: AName:= 'FormUtama';
  1: AName:= 'FormInvoice';
  2: AName:= 'FormReturn';
  3: AName:= 'FormCetak';
  end;
  Result:= FindForm(AName);
  if not Assigned(Result) then 
    raise Exception.Create('Unable to find form named: ' + AName);
end;