this thread.... ugh
i'm shocked your pc has survived as long as it has. i'm assuming you've placed soulseek into ZA as a trusted zone, big no no.. may as well just uninstall ZA. remove that 'network', go to 'firewall', 'custom' (both trusted & internet) add in the ports that soulseek uses. Then do the same on your router, you do have a router right, since you're filesharing you now know that your pc is a target, from both portscanners and your isp...
before really doing all that though, i'd personally start off by backing up all my 'data', is your HD partitioned? multiple drives? external drive/dvd burner. regardless, rip all your stuff off the windows partition (c:). bookmarks, email, mp3, pics, exe, etc. reinstall windows, install ZA, plug into the net, install all OS updates, install avast, spyware blaster, ms antispy, spybot, adaware, firefox or opera, thunderbird, ccleaner, to start with (defrag along the way...).
Now your pc will be 'safer', to do the things you and housemates might do. sorry if all this sounds abit curt, but your pc was being controlled by someone else, sending out dozens if not thousands of spam messages to other equally unprotected folks.
hope this helps some, happy surfing...