Why doesnt rcn ethernet work on my toshiba laptop?

my mother just got rcn and you got internet,phone and tv. they gave her a modem which the ethernet is connect to the home computer for internet.we didnt get the wireless router so i cant connect to a wireless network. I wanted to put the internet on my laptop instead of using the bib computer. so i plugged in the ethernet cord and its says network unidentified. Why doesnt it connect to the internet on my laptop? I have a toshiba satelite l505d. please help