procedure TForm1.FormCreate(Sender: TObject);
begin //sowas hier meinte SirThornberry bestimmt
  SetWindowLong(handle, GWL_EXSTYLE,GetWindowLong(handle, GWL_EXSTYLE) or WS_EX_NOACTIVATE);
  SetWindowPos(self.Handle, HWND_NOTOPMOST + WORD(true), 0, 0, 0, 0, SWP_NOMOVE or SWP_NOSIZE or SWP_NOACTIVATE);
end;

procedure TForm1.SpeedButton1MouseDown(Sender: TObject;
  Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
begin
  keybd_event(ord('A'), 0, 0, 0);//Beispiel
end;

procedure TForm1.SpeedButton1MouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  keybd_event(ord('A'), 0, KEYEVENTF_KEYUP, 0);
end;