what is the model #, ?. Most routers that have a firewall automatically block all inbound ports. Have you had a look around inside your router ? do you see the mention of a firewall. If not you will need to maybe get a software firewall for your pc.
ok, the problem is that, ermm, i wanna block my bro from playing XBL when i play on the PC, hehe, but i dont wanna unplug the cable. I know u can decrease the bandwith usage in a PC, but how to do that on a router?