As Windows 7's market share passes 3.6%, up from 1.9% the day before launch, llManDrakell notes an experiment they did over at Sophos. They installed Windows 7 on a clean machine — with no anti-virus protection — with User Access Control in its default configuration. They threw at it the next 10 virus/worm samples that came in the door. Seven of them ran; UAC stopped only one baddie that had run in the absense of UAC. "Lesson learned? You still need to run anti-virus on Windows 7."