Activer/désactiver/Lancer l'écran de veille

procedure TForm1.Button1Click(Sender: TObject);
begin
if SystemParametersInfo(SPI_SETSCREENSAVEACTIVE, 1, nil, 0) then
label1.caption:='Ecran de veille activé';
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
if SystemParametersInfo(SPI_SETSCREENSAVEACTIVE, 0, nil, 0) then
label1.caption:='Ecran de veille desactivé';
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
//Lancer l'écran de veille
SendMessage(handle, wm_syscommand, SC_SCREENSAVE, 0);
end;