Hello, you have 2 regular options to reset the lost Windows 8 password:
Option 1: Have another Administrator Changed Your Forgotten Windows 8 Password
Step 1: Open the Windows 8 Control Panel.
Step 2: Click on the "User Accounts and Family Safety" link and then "User Accounts".
Step 3: Click on "Manage another account".
Step 4: Click on the "...user you would like to change" the password for.
Step 5: Click on "Change the password".
Step 6: Enter a new password in both the first and second text boxes.
Step 7: In the last text box, you're asked to Type a password hint. This is not required.
Step 8: click the "Change password" button to save the password change.
Option 2: Reset Windows 8 password with command prompt
- Access Window8 Advances Startup Options and click on Troubleshoot, then Advanced options, and finally Command Prompt.
- Type the following command: copy c:\windows\system32\utilman.exe c:\ and then press Enter. You should see a 1 file(s) copied confirmation.
- Enter: copy c:\windows\system32\cmd.exe c:\windows\system32\utilman.exe. Confirm the overwrite of the utilman.exe file. by Y or Yes.
- Remove any flash drives or discs plug on your computer and restart your computer.
- When the Windows 8 login screen is available, you need to click the Ease of Access icon at the bottom-left corner of the screen. Command Prompt should now open.
- Execute the net user command as shown below. Replace myusername with your user name, and mynewpassword with the password you'd like to begin using:
net user myusername mynewpassword
- Close the Command Prompt and login to your Windows 8 with the password you just set.
If the 2 options above don't work you'd better to resort to a third-party tool to unlock the password. Tenorshare Windows Password Recovery Tool is a good one. You can have a try with it.