The only way I know of that someone can get through a NAT router is for you to open up TCP ports to one of your computers (telnet, www,etc) and not take the proper precautions, or set it so you can remotely administer it and have a weak password or worse, not change the default password. With the NAT router I don't have to worry about the latest MS upgrade breaking my firewall software. NAT routers will not stop a mail type virus. For those you need A/V software to scan the mail or be very carefull about opening attachments and clicking on links attached to email. Also you need to be carefull about software you install. It may contain spyware or worse, In this case your Black Ice software will at least let you know if a program is trying to access ports you have not given permission for. A NAT router will just pass it through since it is comming from your side and looks legit. If you tend to install everything you think might be cool to try, (or others that use your computer do) you probably should be running firewall software, A/V software and a program like Adaware to keep the demons out. I have nightmare stories from friends and family whose kids installed every thing they saw on the net, until things quit, then I get a call for help.