Ophcrack is a portable Windows password cracker based on a time-memory trade-off using rainbow tables. This is a variant of Hellman's original trade-off, with better performance. It recovers 99.9% of alphanumeric passwords in seconds.
Cracks LM and NTLM Windows hashes
Free tables available for Windows XP, Vista and 7
Brute-force module for simple passwords
Audit mode and CSV export
Real-time graphs to analyze the passwords
LiveCD is available to simplify the cracking
Loads hashes from encrypted SAM recovered from a Windows partition