How to Reset Your Windows Password using Offline NT Password Registry Editor
Offline NT Password & Registry Editor is a small Windows password removal utility that can run from a CD or USB drive.
Supports all Windows from NT3.5 to Win8.1, also 64 bit and also the Server versions (like 2003, 2008, 2012).
You do not need to know the old password to set a new one.
It works offline, that is, you have to shutdown your computer and boot off a CD or USB disk to do the password reset.
Will detect and offer to unlock locked or disabled out user accounts!
There is also a registry editor and other registry utilities that works under linux/unix, and can be used for other things than password editing.