How to Reset Windows XP, Vista and 7 passwords

This trick enables us to change the password of  Windows Operating system Using Ubuntu 9.10 distribution installed on a usb drive.   Eventhough the titile states on XP, Vista and 7, the trick you are gonna read is also for 2000 and 2003. This method is applicable when you have some Alzheimer’s disease and you forgot your most important Windows login password.  And probably you do some idiotic things with all the password possibilities you know and then your account gets locked up. So there when you stand without knowing what to do, this trick comes to the rescue.
What do you need :

• Unetbootin
• Ubuntu 9.10 ISO (You can also download it using Unetbootin)
• chntpw
• A Usb drive (1 gb or more)

Steps :
First we need to install Ubuntu 9.10 to the USB drive..  Open Unetbootin in a computer other than the target computer (you couldn’t do it on the target computer as it is already locked or forgotten password)

Select Ubuntu 9.10 or Select the “Disc image” option and select the path where you have downloaded the ISO. Select the type as USB drive and select the drive where the usb drive is displayed. Click Ok..

Then Wait..
It installs…
When it is done, click on “exit” and remove the USB drive. Yupeee!! You now have the live image of Ubuntu 9.10
Insert the Usb drive into the target computer. Start the computer, Boot from the usb drive. If it does not come, you may have to change the boot device preferences in the BIOS.
When you boot from the USB drive , the unetbootin options comes and you have to select “default” . Thus it boots into Ubuntu OS. Now you have access to the windows filesystem. Hurray!!
Now we need the tool chntpw. To get this software, connect to the internet and run the command :
sudo software-properties-gtk --enable-component=universe --enable-component=multiverse; sudo apt-get update; sudo apt-get install chntpw
Go to the terminal and change the directory to the password file
cd /media/path/to/disk/WINDOWS/system32/config/
Now run the chntpw tool
# sudo chntpw -u username SAM SYSTEM
When it is executed, it will just erase the password. Now you could restart and log into the windows without the password.
Anyway, as a security precaution , you may backup the data in the hard disk, what if you mess it all up?? lolz..