Step 1: Cain and Abel
You will also need the Rainbow Tables: http://ophcrack.sourceforge.net/tables.php
Cain & Abel is a password recovery tool for Microsoft Operating Systems. It allows easy recovery of various kind of passwords by sniffing the network, cracking encrypted passwords using Dictionary, Brute-Force and Cryptanalysis attacks, recording VoIP conversations, decoding scrambled passwords, recovering wireless network keys, revealing password boxes, uncovering cached passwords and analyzing routing protocols.
This program needs access to your hard drive in order to work. You also need to install WinPcap, which comes with the installer. After downloading the Rainbow tables, extract the files (table0, table 1, etc.) into the Cain folder. The run the program. In the "Cracker" tab, click LM and NTLM hashes. The click the blue cross at the top toolbar and then click OK. this will dump all the users on the computer. Find the account you want to hack and right click on it. Then go to Cyptananylisis attack, LM Hashes and then to Rainbow tables. Click start and wait while the password is decoded. You can then tinker wth the many features of this program