I've been computing since I was 9, never had any installed virus security, never had a virus. If you're stupid and click "Yes" and "Agree" and "Install" on every popup (especially on porn websites, where they tend to be) you'll get a virus. Click "No" "Stop" "DO Not Install" and "Cancel" etc and you won't get a virus. Most file servers now today automatically virus check upon upload by the user, so anything you download from megadownload, rapidshare, even torrent, is "typical" virus free. If you download something from any website that resembles or is http://www.cracks.am/ (don't click this link) you'll get a virus. If you open up an attachment in an e-mail with the e-mail subject line saying "get 4 inches in under 4 days," you'll get a virus.