In this video someone is presenting "a vista hack":http://www.offensive-security.com/movies/vistahack/vistahack.html
in this article there are the 10 Immutable Laws of Security, look at rule #3 where it states: "If a bad guy has unrestricted physical access to your computer, it's not your computer anymore"
Knowing this for years, the movie mentioned does not impress me too much, it gives a nice insight about the (in)security of Vista (if this is the best they can do, ...)