This is a classic Windows 7 workaround. It replaces the Ease of Access button ( Utilman.exe ) with a Command Prompt that has SYSTEM privileges.

Unlike other methods that blank the password, Ophcrack actually recovers it using rainbow tables (precomputed hashes).

This is the legendary free utility that works on everything from Windows 2000 to Windows 7. It works by blanking the password hash in the SAM file.