@dre0017,
Anything you do, you run the risk of losing access to this computer. What is the worst case if you try messing around with system files.... do you want to have to go back to the school to explain why your computer no longer works? So think before you try messing around with system files.
There are several webpages that suggest proxies... I think that they have probably locked down the firewall with an administrator password that you probably don't have. Trying the proxy end arounds is probablly safe.
You could also try a linux boot usb drive.