The mkpasswd program can be used to help configure your Windows system to be more UNIX-like by creating an initial /etc/passwd from your system information. Its use is essential on the NT series (Windows NT, 2000, and XP) to include Windows security information, but the actual passwords are determined by Windows, not by the content of /etc/passwd.
For more information, see this page http://cygwin.com/cygwin-ug-net/using-utils.html#mkpasswd
Thanks to Ron Dozier of University of Delaware for his suggestion.