The ophcrack LiveCD contains a small linux system (SLAX6), 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).
Windows Vista SAM can also be cracked.
It recovers 99.9% of alphanumeric passwords in seconds.
Ref : http://ophcrack.sourceforge.net/
Download page :