Theoretically, a password reset disk Windows 7 can be made with a CD/DVD or USB flash drive. Since USB flash drive is more convenient to carry and safer to preserve, here I highly recommend creating a Windows 7 reset password with USB to prevent your computer from being locked. Below are guides on how to create a Win 7 password recovery USB.

Scenario 1: If you haven’t forgotten your Windows 7 password yet.
At this situation, you can easily make such a password reset USB disc for free to prevent your computer from being locked. Now please follow the below steps:
Step1: Insert the prepared USB flash drive into your computer.
Step2: Type “reset” in the Windows search box and select “Create a password reset disk”.
Step3: When the “Forgotten Password Wizard” appears, click “Next”.
Step4: Select your USB flash drive and click “Next”.
Step5: Once the wizard finishes creating the reset disk, click “Next” then “Finish”.

Scenario 2: If you have already forgotten your Windows 7 password.
Many computer users actually didn’t take any precautions against Windows 7 password forgotten problem before they find they’ve lost or forgotten the password. So if you don’t have such a password reset disk when you forget or lose your Windows 7 password, you need to seek for other ways to make one and then use that to reset Windows 7 password, say a professional Windows password recovery tool—Windows Password Recovery Enhance.
Here’s how to create a reset password Windows 7 USB with Windows Password Recovery Enhance.
Step1: Download, install and launch Windows Password Recovery Enhance on an accessible computer.
Step2: Insert the early prepared USB flash drive to the accessible PC.
Step3: Choose “USB Flash Drive” button to select your USB, next click “Burn” button to initiate the burning process. (Burn the image file of Windows Password Recovery Enhance to USB.)
Step4: Soon you will receive a message box showing “Burning successfully completed”. Until now it means you have successfully created a Windows 7 password recovery USB. Next, just click “Ok” to end to process and then take out the USB from PC.

That’s all about how to create password reset USB disk for Win 7. If you are interested in how to use a reset Windows 7 password USB for lost Win 7 password recovery, you then can refer to:
http://www.windowspasswordrecovery.net/support/enhanceuserguid.html

Source: http://www.windowspasswordrecovery.net/article/reset-win-7-password-with-usb.html