HELP! Vista connection problem

I just got my new computer today, and when i hooked it up and tried to go on the internet its tells me that i wasn't connected to the internet (I have a cable modem). So i ran the network diagnostic tool and it said some cable was unplugged (i don't remember the message), however, my Ethernet (Worked fine last night on my old XP system) is plugged in and the modem is on. When i try to run the Diagnostic tool now it says i can't cause i'm offline.

I'm at my wits end, can someone please please try their best to help me


All replys are accepted thankfully, especially speedy replies
If you have any questions i will attempt to answer them to the best of my ability.

 

Call you Cable provider and tell them that you change computers.

They probably need the MAC number of the New computer.