The first thing which you check if you forget login password. When we install Windows, it automatically creates an account “Administrator” and sets its password to blank. So if you have forget Your user account password then try this:
Start system and when you See Windows Welcome screen / Login screen, press ctrl+alt+del keys Twice and it'll show Classic Login box. Now type “Administrator” (without quotes) in Username and leave Password field blank. Now press Enter and you should be able to log in Windows.
Now you can reset your account password from “Control Panel -> User Accounts”.
Same thing can be done using Safe Mode. In Safe Mode Windows will show this in-built Administrator account in Login screen.

Windows XP and further versions also provide another method to recover forgotten Password by using “Reset Disk”. If you created a Password Reset Disk in Past, you can use that disk to reset the password. To know more about It, please visit http://www.resetwindowspassword.com/

1. Log onto a computer that can link to the Internet. Download Windows Password Unlocker 4.0 from http://www.passwordunlocker.com/products/wpu.html and decompress it on that PC. Note that: there is a .ISO file. Burn the .ISO file to a CD.
2.Get out the newly created CD and insert it to the locked computer.
3.Re-boot the locked computer and then follow the process of instructions. Just after a few steps, the old password will be removed.
4.Set new password:
Step 1: Open the “Control Panel
Step 2: Click the “User Account
Step 3: Select the account you wanna set a new password.
Step 4: Click “Changing Account ” and “Set Up Password”, then fill out the form as listed. Click “Create Password”.

You can use the ISO to burn a boot CD. Follow these instructions:

1. Download ISO file from http://www.windowspasswordsrecovery.com Windows Password Recovery Tool
2. Burn to a CD using a CD burning tool such as Nero or Roxio or MagicISO
3. Insert CD into drive and reboot.
4. You may have to select an option in the BIOS to get the computer to boot from the CD.

Booting up and clearing a password takes a minute or two works like a charm.

You can use the ISO to burn a boot CD. Follow these instructions:

1. Download ISO file from http://www.windowspasswordsrecovery.com Windows Password Recovery Tool
2. Burn to a CD using a CD burning tool such as Nero or Roxio or MagicISO
3. Insert CD into drive and reboot.
4. You may have to select an option in the BIOS to get the computer to boot from the CD.

Booting up and clearing a password takes a minute or two works like a charm.

deleting SAM can corrupt the registry. The Idea is to recover the Password. So that the actual owner never gets to find out that the system has been compromised.

To add to the post, there are two more methods, but they dont actually recover passwords. One changes the password if u have access to any login (even if its a liimited acount), and the second one requires you to repair xp partially (hence u need an xp cd). I can post abt it here if u want To add to the sizzling-info

Awesome post Real informative