Change User Accounts Passwords Without Knowing the Users Password

This article will teach you how to delete users accounts passwords and change them without knowing the users passwords.

Steps

Download the Offline NT Password and Registry editor from http://pogostick.net/~pnh/ntpasswd/
Burn the ISO to a CD-R
Reboot the computer from the CD
When asked, enter 1 to search for NT volumes.
Accept the default path to the Registry directory unless you know it to be different. (Default: WINDOWS/system32/config)
Select option 1 to load the SAM registry hive.
Select option 1 to edit user account data
A list of user accounts will be presented. Type the name of the account you wish to change.
Select option 1 to make blank the user's password, select 3 to make the user an Administrator, select 4 to unlock the account.
Repeat steps eight and nine for each account you want to edit.
- This method works for NT based Windows systems (NT, 2000, XP, Vista, and 7) only, and may not work on 64 bit versions. It does not work for any other versions.

Changing the password for a user on an NT-based Windows system can have repercussions beyond the password itself. If the user has encrypted files using the NTFS encrypted file system, then access to those files will be lost. They may be recoverable by reverting the password back to what it was originally.
There is a roughly 5% chance that this method will fail. The likelihood increases somewhat if you choose option 2 in step 9, which is to enter a new password rather than simply blanking it. Possible failure scenarios include the password not being modified, the password being modified but not to what you intended, or other unknown failures.
Tampering with a computer is illegal in most countries unless you have permission from the owner.