How can I remove the administrator password of Windows 7?

How to enable Windows 7 administrator account and reset lost Win 7 admin password
There are two parts for your Windows 7:
* Enable Windows 7 administrator account
* Reset lost Win 7 admin password
With 240 million licenses sold out in one year, Windows 7 has been proved to be a successful product of Microsoft. Compared with its previous versions like Windows XP, it has many improved features. The built-in administrator account is one of the features. In Windows XP, there is a default administrator account after installation. But the built-in administrator account is disabled by default in Windows 7. To enable Windows 7 administrator account and assign a password to it, you can achieve it in 2 methods.
Part I: Enable Windows 7 administrator account
Method 1: Use Command Prompt
The easiest way to enable the Windows 7 built-in administrator account is to use the Command Prompt.
1. Click Start and type CMD in the search box. Right-click CMD and select Run as Administrator.
2. Click Yes when prompted to allow the Command Processor to run. And then the command prompt will appear.
3. Type net user in the command prompt window, and then hit Enter. All the Windows account user names will be listed. You'll also see the Administrator account, but now it is not enabled.
4. Type net user administrator /active:yes and hit Enter to enable Windows 7 admin account.
Now the Windows 7 administrator account is created. To create the Windows 7 administrator password, you can follow the below steps:
1. Switch to log on Windows 7 with the administrator account.
2. Click Start, Control Panel, User Accounts and Family Safety and User Accounts in order. You'll enter the screen where you can make changes for your account.
3. Click Create a password for your account on the screen.
4. In the coming screen, type and confirm your Win 7 admin password.
5. Enter password hint and click Create Password.
Now your Windows 7 admin password is successfully created.
Method 2: Use Local Users and Groups
1. Click Start and type lusrmgr.msc in the search box, and then hit Enter. The Local Users and Groups screen will come up.
2. Double-click the Users folder. And all the Windows 7 account will be displayed for you.
3. Right-click the Administrator account and select Properties.
4. Uncheck the "Account is disabled" check-box and click OK on the administrator properties screen.
Now Win 7 admin account is enabled. To set a password for the enabled Windows 7 administrator account, follow the steps as below:
1. Right-click the Administrator account and select Set Password.
2. Click Proceed to go on your operation
3. Type and confirm your new Win 7 admin password and click Ok
4. Close the Local Users and Groups screen.
Now the Windows 7 administrator password is assigned to your Windows 7 admin account.
Part II: Reset lost Win 7 admin password
Windows 7 administrator password reset Tips:
Note 1. Please remember to create a Windows 7 password reset disk after assigning Windows administrator password. It allows you to change your forgotten Win 7 admin password when you are locked out of Windows.
Note 2. If you forgot to create the password reset disk, you can choose to use Windows Password Breaker to help create a Windows 7 password reset disk rather than reinstalling the system. Now follow the steps to create the disk to reset Windows 7 password.
step 1. Download and install Windows Password Breaker.
step 2. Run the program and burn a Windows password reset disk.
Step 3. Reset Windows 7 administrator password with the disk.
It is an easy and safe way for Windows 7 admin password reset.

Windows 7 administrator password is the password to any account that's setup to access administrator level functions in Windows 7.
There doesn't actually have to be an "Administrator" user account. What you need is the password to any account that can act as an administrator.
You will need to take a few times to get this password. You may need an administrator login password in Windows 7 if you're trying to run certain types of programs or access certain Windows 7 recovery tools.
Follow the steps below to efficiently find the administrator login password in Windows 7!
Difficulty: Average
Time Required: Finding the password to an admin user may take minutes up to hours depending on the situation
Here's step by step guide:

1. Try leaving the password blank. If there is actually an Administrator account, the password may not exist at all!
   Just press Enter without typing anything when the logon asked for it.
   
2. Enter the password to your account. Often times, depending on how Windows 7 was setup on your computer, the primary user account will also be an administrator user account.
   
3. Try to remember administrator login password. As I mentioned in the last step, your account might be an administrator account, especially if you installed Windows 7 on your computer yourself.
   If that's true, but you've forgotten your password, you might be able to make really good guesses at what the administrator password might be.
   
4. Have another user enter his or her credentials. If there are other users that have accounts on your Windows 7 computer, one of them may be setup with administrator access.
   If this is true, have the other user designate you as an administrator as well.
   
5. Recover the administrator password using a Windows password recovery tool. You may be able to recover or reset an administrator password with one of these free tools.
   Note: Some password recovery tools on the list I have in connection with the above change and the ability to set user accounts in Windows 7 Administrator account. This can be useful if you know the password, but it is not an administrator account.
   
6. Perform a clean install of Windows 7. This is a last resort option. This type of installation will completely remove Windows 7 from your PC and install it again from scratch.
   If you're just curious about the administrator password, I would not recommend this resort. However, if you need an administrator password to access the operating system of diagnosis and this is your last effort to save the computer running a clean install will work.
   Keep in mind that it is a time consuming process due to the fact that all of your data must be backed up and then later restored.
   

Tips:
Looking for your administrator login password but you don't have Windows 7? See How to Find Windows Administrator Passwords for instructions tailored for other Windows operating systems.

Microsoft Windows 7 is the latest version of Microsoft Windows operating system. Compare to its predecessor Windows XP and Vista, Windows 7 is more powerful and more secure. Unlike Windows XP, Windows 7 adopted a new password protection system that we can't use the hidden administrator account by default. The problem is that when Windows 7 administrator password lost, we can no longer recover our lost password by using the hidden administrator account. Therefore, how to recover the Windows 7 Admin password if we lost or forgot it?

Don't worry, here are two methods for Windows 7 administrator password recovery:

Method one: Use another Windows 7 administrator account

If you had created more than one administrator account on your Windows 7 computer and you can remember the others admin password, you are lucky. In such a case, you can change one of the administrator accounts' password if you login with another administrator account. What you need to do is just following these 3 easy steps:

Step 1: Click Start -> Control Panel -> Add or remove user accounts

Step 2: Choose the locked administrator account.

Step 3: Click Change the password or Remove the password. And then you can change or remove the lost or forgotten password.

Please note: If you select this method, the locked Windows 7 administrator account will lose all EFS-encrypted files, personal certificates, and stored passwords for Web sites or network resources.

However, if the locked account is the unique administrator account on your Windows 7 computer, you can try the method below.

Method two: Use third party Windows password recovery software

There is plenty of software which is used to recover Windows password available online. You can choose one of them to create a Windows password recovery disk and use the disk to recover Win 7 Admin password. I recommend Windows Login Recovery. Then you can follow these 4 easy steps:

Step 1: Download the software and install it on another computer which has a CD/DVD writer.

Step 2: Run the software and burn the ISO image file into a blank CD/DVD.

Step 3: Recover Windows 7 administrator password with nearly burned password recovery disk.

Step 4: Reboot your locked computer without a password required.

Now you can regain access your Windows 7 operating system and create a new administrator password. The best thing of using this method is that you shouldn't lose any data on your computer. Furthermore, If you can't find a computer which has a CD/DVD writer or the locked computer have no a CD-ROM, You can burn the ISO image file into a USB flash drive and use the USB flash drive to recover your Windows 7 administrator password.

Try these two methods the next time you lose or forget your Windows 7 administrator password, which you do not need to reinstall Windows system for getting back to Windows by removing lost or forgotten password.

An administrator password in Windows 7 is the password to any account that’s setup to access administrator level functions in Windows 7.
There doesn’t actually have to be an Administrator user account. What you need is the password to any account that can act as an administrator.
There are a few times when you will need this password. You may need an Windows 7 administrator password if you’re trying to run certain types of programs or access certain Windows 7 password recovery tools.
Follow the steps below to quickly find the Windows 7 administrator password!
1.Try leaving the password blank. If there is actually an Administrator account, the password may not exist at all!
Just press Enter without typing anything when asked for it
2.Enter the password to your account. Often times, depending on how Windows 7 was setup on your computer, the primary user account will also be an administrator user account.
3.Try to remember the Windows 7 administrator password. As I mentioned in the last step, your account might be an administrator account, especially if you installed Windows 7 on your computer yourself.
4.Have another user enter his or her credentials. If there are other users that have accounts on your Windows 7 computer, one of them may be setup with administrator access.
5.If this is true, have the other user designate you as an administrator as well.
6.Recover the Windows 7 administrator password using a Windows password recovery tool. You are able to recover or reset Windows 7 administrator password with Windows Password Unlocker
7.Perform a clean install of Windows 7. This is a last resort option. This type of installation will completely remove Windows 7 from your PC and install it again from scratch.
If you’re just curious about your administrator password, I wouldn’t suggest this extreme solution. However, if you’re needing the administrator password to access operating system diagnostic tools and this is your last effort to save your PC, performing a clean install will work.
Keep in mind that it is a time consuming process due to the fact that all of your data must be backed up and then later restored.
Reference: How to find Windows admin password?