One Computer blocked...

Here is the situation:

My computer at work has a connection to the internet through the works gateway. The work computer is logged onto a domain and has full function to connect with any of the internet. There is nothing blocked by surfcontrol aside from sites flagged as used for setting up annonymous ips. Aside from that nothing is blocked on the computer.
For the last few months I have been using a pc i built that only contains IE and a copy of warcraft that I would connect using the work pcs ethernet cable.
The only thing that it initially required was to turn off fast user switching. After that change it worked fine with nothing blocked.
Tonight when I turned the machine on everything was blocked. Any connection to the internet resultes in surfcontrol any connection to warcraft causes a surfcontrol message. But on the original work computer nothing is blocked still.

So questions.
Is there a way to the extra computer I brought in and only that computer from connecting?
What information can be used to block the computer? IP or comp ID maybe?

Any suggestions

 

Sounds like someone upset the IT dept. a little too much. Most likely they saw a foreign machine on the network, and blocked it. Nothing more that I can say at this point, but you will probably get a letter or a talking to by the upper echelon here soon.