just like you're not supposed to. It sounds like the PC it's attached to is logged in under very specific settings to allow access to the school LAN by that specific PC only.
You're SOL.
I brought my laptop to school because i have a couple hours of freetime each day, and i wanted to play world of warcraft during that time. but when i take the ethernet cable out of the desktop pc i use there and plug it into my laptop, it says that its connected but i can't get on the internet nor WoW. Is there something im forgetting to do. I can't really talk to network admins either because im not really supposed to play games at school.
its a broadcom Netxtreme 57xx Gigabit controller, and it says it connected and has a speed of 100mb/s, but i still don't have internet access.
any way to solve the problem.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic