Are you referring to the Microsoft Fingerprint Reader ? See this page:
http://www.microsoft.com/hardware/mo...pe=Fingerprint
It can associate different fingerprints for different windows user accounts.
The install notes says that the product is for convinience only and is not a true security feature. They still recommend using strong (complex and long ) passwords. I have read somewhere that a fingerprint on a gummy bear can be used to fool it.