[PhoeniX]

Только что проверил, помогло, ок?

Код:

procedure TForm1.FormActivate(Sender: TObject);
begin
  ShowWindow(Application.Handle, SW_HIDE);
  SetWindowLong(Application.Handle, GWL_EXSTYLE,
  GetWindowLong(Application.Handle, GWL_EXSTYLE) or WS_EX_TOOLWINDOW);
end;

Код:

begin
  Application.Initialize;
  Application.MainFormOnTaskbar := False;
  Application.CreateForm(TForm1, Form1);
  Application.Run;
end.