Sorry, I can't recommend one of the "Anti-Spyware/Anti-Virus/Anti-Rootkit" because I don't use them (my connection to the internet is through a Linux machine which has its own firewall).
(hide) If you want to play a game with an opponent of a similar level, you can define a required BKR range for a new game invitation. Then nobody with a BKR outside this range will be able to see/accept it. (Katechka) (show all tips)