Cannot connect to internet through ethernet

[Polnadian]

I'm not 100% sure if this is the right place to ask this, but if it isn't, I'll delete it if need be.

Anyways, in my college dorm, there are ethernet plugs in the wall. Yesterday, the internet was working fine, but today, when I tried using the internet, it'll connect to the (router? group?), but it won't connect to the internet. I've tried the same plug with my roommate's Macbook, and it worked just fine, so I am assuming it is a problem with my computer (or my own incompetence). Normally, I would just try restarting my modem, but that isn't an option here.

Specs:
Intel Core 2 Quad Q9650 @ 3GHz
Zotac nForce 790i motherboard
4x2 crucial 1333MHz RAM

 

[hang-the-9]

When you connect to the cable, reboot with the cable connected, and try again. Also do an ipconfig command at a dos prompt, post what you get here.

Contacting the school IS should help also, they can actually check things on site.