Hey Guille,
Sorry you haven't been receiving our support replies, I think your spam filter might be capturing them. I recommend adding
support@telltalegames.com to your safe list.
DjNDB has walked you through everything we would try and the situation with your computer is frankly stumping us. Your newer computer should definitely be compatible, but we're out of new things to try. I'm afraid I can only apologize and offer you a refund at this point.