Brian, I use Sygate personal firewall which runs fine when in servers and blocks all the nastys without any fuss. You can download it HERE, Its free a free trial version, But thats what I use and has no time limit. I would try leaving this on and disabling your Norton for online gaming. Initially sygate will ask if you want to allow Heat to access net (as it will any other programs) Simply answer yes or no as applicable and check the box...remember this answer.
I know all programs dont work for everyone, But give it a shot.
Cheers
Phil
