Can not remove proxy settings ..?

I was at a place where I had to go into some specific web proxy configuration data to access the Internet. The proxy is 172.20.0.2 (8080) and now, even if i uncheck the boxes, Internet still not working. I tried to diagnosis, which could not be said connect to the web proxy (172.20.0.2), but I already unchecked … I tried out the registry, but still coming over and over again .. What else more I can do? PS my Apple Safari browser works very well so its only in IE.

The following page shows how to remove the proxy settings in IE and Firefox. http://www.surfbouncer.com/personal_vpn_proxy.htm

Unblock websites at school!