It sounds like you've got a "spy bot" of some sort when you got the viruses. Download [link|http://www.safer-networking.org/index.php?lang=en&page=download|Spybot Search and Destroy] and run it on your system.
If you find Mozilla to be too slow, you might try [link|http://ftp.mozilla.org/pub/firebird/releases/0.6.1/MozillaFirebird-0.6.1-win32.zip|Mozilla Firebird (direct download link)]. It's a lot less piggy than Mozilla and works well in my limited testing.
HTH. Good luck!
Cheers,
Scott.