Using laptop on someone elses cable connection

[Guest]

Hey all, Im staying at my uncles on vacation and he has time warner cable broadband. I brought my laptop and tried just swapping the lan cable from the back of his desktop into my laptop to get internet connection and it wont work. Is there anyway i can make this work or will i need a router?

 

[Catsrules]

It should just all auto configure and work. Unless your laptop network card is set to be a static IP
What OS are you useing?

I wonder if the ISP have only allowed your uncles desktop MAC address to the internet. My friend's ISP did that to him.