PunkBuster is a mother-trucking pain in the behind. Seriously. So many people have been getting so many issues with it lately, such as being dropped from games, constantly. I have been banned from servers for periods of time because of PunkBuster.
Do you have your lines split, or running a router?
I had to get a tech in to rewire a portion in my apartment because I was unable to split the line with a splitter; it would cause alot of connection problems.