The scariest thing I ever saw was when I booted up a brand new out of the box laptop and plugged it into broadband only to have a virus hit the system within 10 seconds (no internet explorer or other browser was open). Luckily the laptop came pre-installed with the awful panda anti-virus and stopped it. This was Windows XP with (at the time) the latest Service Pack 1.
Happens to everyone :PThat's one of the positive points to wlan in Linux being so much bother to set up.