Ophcrack is a Windows password cracker based on a time-memory trade-off using rainbow tables. This is a new variant of Hellman’s original trade-off, with better performance. It recovers 99.9% of alphanumeric passwords in seconds.” <- taken from sourceforge.

What do you need:
1. Physical contact with the computer.
2. CD with Ophcrack on it.
3. The computer must be able to boot from CD(which shouldn’t be a problem).
(you don’t need limited user access or anything else)

How to use:
(First download the image file from the provided link, and burn it to a CD.)
After you have the Ophcrack Live CD:
1. Make the computer you wanna crack in to boot from CD. For those who don’t know how, just enter into the BIOS and search for a boot priority, just change the sequence to boot from CD first, save changes and exit.(if you don’t know how to access the BIOS search google for it, also google may help with the boot priority).
2. Enter the CD and reboot. It will boot up to linux, and you’ll be able to handle it from there. It might ask you ‘which partition’ you wanna scan, and everything else will be done by itself. It will find the password for every user on that disc partition.
3. Have fun!;)

Download