YOu know how they say if a pro wants to seal you car no alarm will help you.
Well the same can be said for securing up your computer.
The basic Norton, Spy Bot S&D will help, Windows firewall is a joke.
The best approaches use external drives that can be disconnected and are never online... This is where your important data shroud be...
Virtual machines that are trashed when off and proper network security are the only way to be safe...
Physically disabling your Network when not is use is a good move.... Powering it off is not enough with POE i can still get in... I mean they can still get in