Ethernet Connected but no internet

Hi everyone!
I'm a new convert to Mac, better late than never ;D

I installed Lion on my MacBook Air lately and I'm connecting it to Ethernet here at work but I'm unable to browse the internet or check my emails with it. I turned off Wifi so it doesn't get in the way but still no success.

I ran a Network->Assist me -> Diagnostics -> Ethernet and the result is positive. So if I'm connected to the Ethernet, why is it that my programs can't seem to be able to use it?

Your helps is much appreciated!

How are you connecting with an ethernet cable? The MBA doesn't have an ethernet port.

The other question, is does your company allow internet access to outside computers. I can plug in my personal laptop at work, and even connect to the WiFi, but that is where my access ends. It connects to a network, but it will not connect to the internet.

I bought an adapter and connecting to the USB port.

I have connected to the internet through Ethernet before without a problem, it's only when I updated to Lion I can't do this anymore.

Does it need a driver? I know that sometimes stuff like this needs a driver in order to correctly work.