"the network cable is disconnect"

[Carles Costa]

Hi everybody,
(the last post I thought in spanish; excuse me, I'll try to explain in
english)

I have a problem with a computer which I had never seen it... "the
network cable is disconnect"

I explain:
I go to "administrive my computer" and there are there a ethernet wich
"work correctly". Then, i put/plug the cable, and the computer tells me
"the network cable is disconnect"
I try another cable but it tells me the same
I try another router jack (a hole where you plug the cable) to plug the
cable, but it tells me the same
I try with another ethernet, but it tells me the same
I also try with an usb/ethernet adaptor, but it tells me the same

What happen?

Thank you very much and excuse my for my english

Carles