No enciende mi laptop Latitude E5440

Hi @Alejandro001 

You may have more luck writing on the Spanish speaking community board.
‎Comunidad de Dell | DELL Technologies

Otherwise I can offer you some help in English, but you should explain a little more precisely what is going on with your laptop.
Are you saying it won't power up? 
Is there any sign of life at all, for instance can you hear the fan spinning, do you see any led lightning up or blinking, do you hear any sound?

If the answer to all of these questions is no, and you are 100% positive that the AC adapter is not defective, you should try resetting the RTC and see if anything happens, following this official steps: Cómo restablecer el reloj en tiempo real (RTC) para recuperar una laptop Dell | Dell España

If this attempt fails too, just remove the battery altogether and use only the AC adapter to power up the laptop, to exclude any issue with a failing/shorting battery. If the laptop won't power up, and again you are positive the AC adapter is fine, then it's time for you to contact a local shop and see if it can be repaired.
You could try contacting Dell out-of-warranty Support in your country and ask for a quote, but other than the fact that it might be very expensive, I am afraid they won't service a 2014 model any more :(