You may always hear of the similar complains like "I forgot Windows 7 password on boot. Although I could log onto other accounts, but I could not download anything without admin account. How do I get it back?" Some other people would say "I have changed my Windows 7 administrator password in that my son downloaded too much things onto the computer, but now I forgot the password. What should I do without a Windows password reset disk?"
There would be more and more PC users getting into the similar issues nowadays which always made their life in a mess. And large number of them would ask for help from Yahoo Answer just as below:

It seems to be a fast way to get the answer from Yahoo Answer or other FAQ sites, however, it could not offer you the most satisfied solution. Here, we gathered Top 4 methods and some windows help sites for Windows 7 password reset issues.
A Windows password reset disk is always used to reset Windows password if you have created in advance. Here are the steps to use the disk for your password recovery.
Step 1: If you enter the wrong password when you attempt to log on, Windows will display a message that the password is incorrect. Click "OK" to close the message box.
Step 2: Click "Reset Windows Password", and then insert Windows password reset disk (or other removable media).
Step 3: Follow the steps in the "Password Reset Wizard" to create a new password.
Step 4: Log on with the new password.
Reference: How to Create Windows 7 Password Reset Disk For Free?
Notes:
1. It cannot be used to reset Windows password on another computer.
2. Keep the password reset disk in a safe place in case of others' access your computer.
3. Take the disk for Windows password reset if you lost the password next time.
Step 1: Log on to the account who owns the credential of an administrator account.
Step 2: Click the Start button
with typing lusrmgr.msc into the Search box, and press "ENTER".
.Then "Local Users and Groups" opens. If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
Step 3: Double-click "Local Users and Groups", and then click Users.

Step 4: Right-click the account that you need to reset the password for, and then click Set Password.
Step 5: Type and confirm the new password.
In the Command Prompt you can monitor all the user of the computer by typing some commands.
Step 1: Press Win Key+R and type cmd in the Run command box and hit enter to open command prompt. And then type net user in the command prompt and hit Enter. The Command Prompt will show you all accounts on the Windows 7 PC.

Step 2: Type net user xyz (xyz is the locked admin account's name and 123 is the new password) and press Enter. Now you have successfully created a new password on the locked admin account.

Step 3: Type shutdown -r -t 00 and press Enter.
Your Windows 7 PC should be rebooted automatically and then you can log in Windows 7 with the new password. It is a simple and easy way to change the password of any users from the Command Prompt.
But the drawback of this technique is that you can’t solve Windows 7 password recovery issues if you do not have the Administrator Privileges. So it is quite hard to change the Windows password of the users without logging in as the administrator.
It is better to DIY a Windows password reset CD/DVD or USB to reset Windows 7 password without reinstalling the system. Just follow next 4 steps, you can enable to handle this Windows Password Unlocker with ease.
Step 1: Download and install Windows Password Unlocker Professional(Trial Download)
Step 2: Burn a bootable CD/DVD or USB.
Note: A USB flash drive is well-recommended as its tiny size but large space.
Step 3: Set your target computer to boot from CDROM or USB flash drive
Step 4: Insert the burned CD/DVD or USB flash drive into the locked computer. When a window pops up with all your account names, select the target one to reset its forgotten password.

Reference: How to Reset Windows Password with Windows Password Unlocker?
Well, there are so many methods to solve your trouble with Windows 7 password lost, of which depends on your convenience. If you have another available Windows 7 admin account in hand, it will take less time to remove or change Windows 7 password in Control Panel. Go forword with Start button and follow its guide to remove or change the Windows password instantly.