How's it work? By tricking you into running the virus by modifying the way "autorun" works when you plug in a drive. Look closely at the screenshot above and you'll see two entries for "Open folder to view files." The one at the top is a phony entry that actually installs the virus on your machine... but of course it's the default selection that pops up when you plug in a drive. Once installed, the virus spreads like crazy via a separate flaw in Windows networking system (now patched, so be sure to run Windows Update if you haven't lately) and can quickly infect a whole office.