A lost Windows password used to be a "near-despair experience". Surely any tech support can detach your computer's hard drive and copy your files then do a reformat. This works good, but you still do not know the password. Sometimes, knowing the password is more important rather than acquiring the files inside.
Ophcrack is a tool for revealing (also called "cracking") a windows account password. Some paid applications will allow you change the account password so you can regain access, while this is nice, Ophcrack instead reveals and cracks the password using hashes and rainbow tables.
Download and Run the Ophcrack Live CD- Browse to the official Ophcrack website Ophcrack
remember to download Ophcrack only from its official website and download links as hosted by SourceForge
- Download the correct version for the Windows operating system that you want to crack. Notice that the download is a .ISO file that is ~400mb. The file is quite huge as it contains the hashed tables of password input that ophcrack will use during the recovery.
- Burn the downloaded ISO file into a bootable disk
- Boot the target computer using the ophcrack cd
- Ophcrack will run a few command line screens and then present you with the main menu - select the default option
- Ophcrack begins it password cracking process. Notice that it detects all usernames and indicates the cracked "NT Password"
In the example above, Ophcrack has determined that an "administrator" account exists and its password is "K477Ekylling07".
With great power comes great responsibility - Ophcrack
Ophcrack basically a password cracking tool. Such password cracking tools are sensitive tools to be used only for proper password recovery purposes. Ophcrack has generously been created free by "Objectif Sécurité Group" so that it can aid system and network administrators recover lost or forgotten user and administrator passwords. It is not to be used maliciously or to "hack" and steal passwords.
Ophcrack is not a virus or malware 
The screenshot above is my computer's McAfee antivirus detecting my download of Ophcrack.
Ophcrack may be considered by some antivirus/antimalware companies to be a "potentially unwanted file" or even a virus or trojan. This is why Ophcrack is primarily to be used by qualified system administrators and tech support representatives. The real Ophcrack from SourceForge website is not a virus or malware. Because of its "password cracking", some antivirus and antimalware programs may categorize ophcrack to be a threat.
