[Casimiro Notevi]

Código Delphi [-]
function SecondsIdle: DWord; var liInfo: TLastInputInfo; 
begin 
  liInfo.cbSize := SizeOf(TLastInputInfo);
  GetLastInputInfo(liInfo);
  Result := (GetTickCount - liInfo.dwTime) DIV 1000;
end; 

procedure TForm1.Timer1Timer(Sender: TObject); 
begin 
  Label1.Caption := Format('System IDLE last %d seconds', [SecondsIdle]);
end;