Solution: Use Windows Password Breaker Professional
With respect to reset admin password on Windows 7, the best choice is to use a Windows password reset apps. Here I highly suggest Windows Password Breaker Professional.

Windows Password Breaker is one of the good Windows password reset tools at present. It can help you reset forgotten administrator and other user passwords by creating a bootable password reset CD/DVD/USB drive in any computer. This tool works all latest Windows versions, like Windows 7/Vista/XP/2008/2003/2000.

What worth mentioning that you can instantly get back into your computer by using this program. It just requires you a few minutes to reset the forgotten administrator password, no matter how long and complicated your password is. 100% security is guaranteed. No need to worry about any loss or damage to your computer data and settings. And its success rate is nearly 100%.

The only drawback of tool is that Windows Password Breaker is released as shareware. Its trial version can display the user accounts on Windows for you to make sure that it is compatible with your computer. If you want to reset the user passwords, you have to pay for it to get the full version.
To get started, please take the following steps:
1. Download and install Windows Password Breaker in any computer.
2. Burn a bootable password reset disk with CD/DVD/USB device.
3. Boot the locked computer form the burned disk.
4. Reset forgotten administrator password under DOS command prompt.

That'll. Next you can log into your Windows 7 without password. Please note that Windows Password Breaker has 2 other editions in addition to the Professional edition. Windows Password Breaker Standard only resets login password on Windows 7/Vista/XP by creating a bootable CD/DVD. While on the other side, Windows Password Breaker Enterprise resets not only local administrator and other user passwords on Windows 7/Vista/XP/2008/2003/2000, but also domain administrator password for Windows servers (like 2008/2003) acting as domain controllers.

In reality, you don't have to use Windows Password Breaker Professional if you can still log into Windows 7 computer through another user account with admin rights. In that case, you can simply reset Windows password the administrator password on computer as follows:

Option 1: Use "lusrmgr.msc"
Step 1. Log into the admin account, type "lusrmgr.msc" in the Search box, click Ok.
Step 2. Expand the folder titled users on the Local users and groups window.
Step 3. Right click the username for which you want to change the password and select Reset Password.

Option 2: Use "Control Userpasswords2"
Step 1. Log into the admin account.
Step 2. Press Win +R to bring up the Run box, type "control userpasswords2" and click Ok.
Step 3. This will open the classic user accounts management window. Select any user and select reset password.