請各位Ching听一听。Beside installing antivirus program , you'll need a software firewall, even though you may have a hardware firewall on your router. NAT on your router is not good enough. If you go for a hardware firewall, look for one with "stateful packet inspection". For those of us who can't afford one, we need a software firewall. One of the best is COMODO Firewall 2012. 它是我自己最好用之一個防火墙软件。