Many reasons attributed for Windows 7 passwords being forgotten or lost.
Before we find a certain solution to unlock the forgotten Windows 7 administrator password, we need to know the reasons why they were forgotten or lost. Thus in the future or after we successfully unlock the password, we then can avoid similar problem as possible as we can.

1. The Windows 7 password is difficult to remember, long, arbitrary and complex.
2. Frequently changing the password.
3. Having long time away from the computer.
4. Got computer hacked by others etc.

After we get to know how we forgot or lost our Windows 7 password, we now can start to unlock password Windows 7 with purpose. Step-by-step tutorials on how to unlock Windows 7 admin password

Solution 1: Use Windows 7 built-in Administrator Account.

You may not know the Windows 7 built-in Administrator account which has full privilege over the computer is without password protected by default. This is because it is hidden so that you cannot notice of it. Therefore, we can unlock password Windows 7 with it if no change to its default settings.

1. Start computer and then press “Ctrl+Alt+Delete” twice at Windows Login Screen.
2. Type “Administrator” without quotations in the username box and leave password box blank. Then hit “Enter” to log onto Windows system.
3. Go to “Start->Control Panel->User Accounts” to unlock the forgotten Windows 7 password.

Solution 2: Use a third-party application—Windows Password Recovery Professional.

If you are asking for an easy and more credible solution on Windows 7 password unlocked, I would recommend you to use this Windows Password Recovery Professional since pretty a lot of computer users have changed the default settings of the Windows 7 built-in Admin account in their computers for safety consideration.

However, if you cannot gain access to or unlock your computer with the built-in admin, your only solution goes to use a third-party application. Below are the step-by-step tutorials on how to use Windows Password Recovery Enhance.

How to unlock Windows 7 password with Windows Password Recovery Professional?
Step1: Download and install Windows Password Recovery Professional on any accessible computer.
Step2: Run this program correctly, and next insert a blank and writable CD/DVD/USB Flash Drive to this PC.
Step3: Using the program to burn a bootable CD/DVD/USB (Windows 7 password reset disk).
Step4: Put the newly created CD/DVD/USB to the target computer and perform unlock windows 7 password with it.

With only 4 steps, you then can regain access to your locked computer within 2 minutes. Isn’t it cool?

Related Article:
http://www.recoverlostpassword.com/article/forgot-windows-7-password.html
http://www.recoverlostpassword.com/article/break-win7-password.html

Source: http://www.reset-password.net/unlock-win7-admin-passoword.html