I'm going to be as useless as possible here, because I really don't know any more than this:

I download torrent files. Sometimes they lag up my gaming experience, so I pause the downloads. Internet access promptly becomes non-existent. I lag out of IM programs. I can't load webpages, and my online game disconnects. My pinging of yahoo.com times out.

I re-start the torrents and all is fine in the world. What's going on?