Ethernet connected but unable to load pages
I'm currently studying and staying in student accomodation abroad, where the internet connection is from a wall jack. I bought a new ethernet cable and handed in my (ethernet) MAC address. I'm using the late 2011 15" Macbook Pro, with Lion. I've run the diagnostic check multiple times and every time I get all green, but I still can't load any pages. I've spent hours looking for answers online, but although there seem to be a lot of people having problems, nobody seems to actually get an answer! When I registered the MAC address I had to choose a username and password, but I've tried using this with PPPOE settings (No PPPOE settings found in the network) and also with proxies, but as I haven't been given a proxy code that doesn't work either.
I've spoken to the office who have told me that there are no proxies required, and if I can't connect it must be my computer. However, I just spoke to a technician at the university who told me that as I can connect to the university wifi network without any problems, the problem must lie with the network itself (possibly that I need to connect to a proxy server).
I vaguely rememeber having problems connecting to the wireless at home when I first got the computer, it was something to do with Lion connectivity issues, could this be the problem with the ethernet? (Unfortunately I can't remember how I fixed this!!)
Can anyone shed any light on why I can't connect and settle whether it's the network or my laptop?!
Thanks
MacBook Pro (15-inch Late 2011)