I have 3 pcs connected to a wireless router, and one of the users is downloading tons and tons of stuff. How can I limit the amount of bandwidth that he can use? If I can't do this, can I disable the port that the downloading program runs on?

First issue is: Who is paying for the ISP account and what is the roomie downloading? Who ever is responsible for the ISP account will be the one the FBI comes after if the roomie is downloading stuff illegally. Your question: yes, you can usually block ports using the router setup. Go here to see if the program is listed, so you can see what ports it uses. http://www.portforward.com/ Search Engines Are Your Friends ☺ Morpheus: There is a difference between knowing the path and walking the path. "The Matrix"

Even easier, tell him to keep his $$$ (assuming of course he's actually sharing the cost of the internet connection) and unplug him. Let him get his own account and that solves all your problems.

That would work, but I want to share the cost. Is there a way to limit bandwidth to one computer on the router?

not unless you have a higher end router , these cheap home units won't cut it for doing bandwidth limiting .

Try google searching "bandwidth limiting software" and a few other similar strings. I suspect there are probably software applications out there that will do this for you.