This is possibly just one of many ways you can get access to a computer running Vista. The crazy thing about this exploit is that all you require is a Live Linux CD that allows you to copy/rename files on an NTFS partition. There’s no dearth of those, the one used in the video is called Back Track
The steps are very, very simple; even your grandma could do it! All she’d have to do is watch this video and follow the same steps.
Scary? You bet!
Update: There’s quite a lot of discussion on Slashdot about this including people pointing out that a variant of this hack was available on Windows XP and 2000 too. But the more important point made was that if you have physical access to a computer and that computer’s hard disk is unencrypted (both of which are prerequisites for this hack) then you pretty much own the computer anyway. I guess the utility of this hack is for SysAdmins so that if they ever find themselves with a Vista box without a password, this is a useful way to get in.