The one that is usually suggested is Offline NT Password & Registry Editor
That creates a bootable cd - is well known and perfectly legal to change your own password.
Hacking into some one else's machine is not a good idea.
There are several that you have to pay for which are probably simpler.
There are also other methods in the tutorials. Password - Change from WinRE Reset your Windows Password in Regedit at Boot
It is exteremly easy to get round windows Password.
It is only intended to deter the casual paaser-by from having a quick peek at your laptop contents.
If you are daft enough to keep e.g. sensitive bank info on your pc - you had better encrypt it in some way - or keep it in a separate protected folder.