If you have a router, you could go in and block the ports they are hitting if you want, just be carefull and not block ports you need. Look in Zonealarm and see if it's always the same IP. A program called visual route, could trace it back to the source so you can see if it's always centered in the same local, it'll also tell you who it's from to a point. Also if your using file sharing programs it could be that they are still trying to download shared files.