Many of you are familiar with L0phtcrack for cracking passwords. LC5 was discontinued by Symantec in 2006, but you can still find the LC5 installer floating around. The free trial only lasts 15 days, and Symantec won’t sell you a key, so you’ll either have to cease using it or find a key generator.
Ophcrack is a Windows password cracker based on rainbow tables. It is a very efficient implementation of rainbow tables done by the inventors of the method. It comes with a GTK+ Graphical User Interface and runs on Windows, Mac OS X (Intel CPU) as well as on Linux.
The ophcrack LiveCD contains a full linux system (SLAX), ophcrack for Linux and rainbow tables for alphanumerical passwords. The LiveCD cracks passwords automatically, no installation necessary, no admin password necessary (as long as you can boot from cd).
More information about this tool can be found here: http://ophcrack.sourceforge.net/