Short answer: You can't. Long answer: it's not only their network but the computer is theirs too. Messing with other people's computers is a Bad Thing™ which can get you expelled, charged with damaging the computer and made to pay for the repair-or the whole computer.
These forums do not support "getting around" any admin functions on OTHER PEOPLE'S PROPERTY.
Now for the lecture: You're at school to LEARN, not to chat with other people. The computer is provided to help you learn. Use it for what it was provided for and don't whine about not being allowed to screw around with it. I have a number of classmates who bring their personally owned computers into our college classes and instead of typing notes with them, they chat and do other non-learning things. The term for these people is "failing college students." If you pay attention in class, you'll do better in class.
Finally, read the announcement at the top of each forum. Your thread title sucks. I'm amazed that wataru (or anyone else) bothered to answer you before a moderator came through and told you to read the rules before posting.
I know it sounds like we're all coming down hard on you, but those are the rules-both covering the school-provided computer and these forums.
Welcome to the MacNN Forums, and when you have a problem that we CAN help you overcome, we'll all be happy to do so.