Per Digirati: Surely he has an active firewall installed and a current AV/AM solution. He probably conducts periodic cleaning of crud and supplemental scanning with "on-demand" tools. He most likely has physical control over access to the computer, that is, it is not in a public area, or used unsupervised by unknown users - but rather used by just him, and maybe another "trusted" user. If using wireless, he has probably changed access defaults and uses the highest security possible. It is not likely he frequents P2P sites and participates in illegal filesharing of copyrighted materials, illegal porn or illegal gambling. He can recognize suspicious attachments and downloads and likely scans them before opening, and he probably does not click on every link he sees, wondering where it might take him.