Ziv
To answer your question, the problem was that one of the 8 wires in the cat 5 bundle was torn, so I had to identify and eliminate it, also as to your cross wire soloution I found out that it is the correct solution when you connect two computers directly however, what we had was a router to computer, a different set up
Anyway thank you for your

And to all the others, thank you for your kind words
Moshe Grad