I found this piece of free software earlier, from Banana Security, called “BananaScreen” – it’s a replacement for your username/password login screen, which uses a webcam attached to your computer to let you in! As a bonus, the software locks the computer if you walk away from it, and unlocks it when you come back. All you have to do to get started is download the software and create a face model using your webcam. Works with Windows XP (but I’ve heard it works with Vista, although it is unsupported.)
http://www.bananasecurity.com/banana2.swf
Login to Windows using facial recognition software
ICT Nuggets 
It doesn’t work with vista, it goes but then once you run it, it thens shuts comoputer and gives blue screen if u know how to fdix this then email me 16.ruls@gmail.com