By saying at home, and wireless hookup, I am guessing that you are talking about someone on your network... Well... You can set controls on that person to stop them from accessing files in shared folders by hiding them... Does someone know your password? Which operating system are you using? Also, I suggest keeping up with Windows Updates weekly (if not done already)... Microsoft is constantly coming out with security updates, etc.
[glb]Flame[/glb]