When you forgot Windows 7 password, you can log into another admin account and change the password. And this also works when you forgot a Windows 8 local user password. Here you will find out how to reset a lost Windows 8 password with another admin account.

Steps to reset lost Windows 8 password with another admin account
Step 1:Log into the target Windows 8 PC as administrator.
Step 2:Press Windows + I to open the settings window, type user accounts in the search box, and then click on User Accounts in the search results.
Step 3: Click on Manage another account one the coming User Accounts window.
Step 4: All user accounts on the PC will be listed. Select the account you want to reset password of.
Step 5: Type a new password for the selected user account, type it again to confirm it, type a password hint and then click Change password button. And the lost Windows 8 password will be changed to a new one soon.
Note: The selected user account will lose all EFS-encrypted files, personal certificates, and stored password for websites and network resources.

What if you forgot Windows 8 administrator password?
Forgot Windows 8 password? An alternative way is to reset it with the password reset disk created ahead of forgetting the password. Users can easily create a password reset disk for local user account.

Reference: How to create and use Windows 8 password reset disk?
Forgot to create such a password reset disk? Don't worry! Windows Password Unlocker will do you a favor. With this Reset Windows password program, you can create a bootable Windows 8 password reset disk with CD/DVD or USB flash drive in seconds. Once the boot disk is created, you can take the following steps to reset Windows 8 password.

Step 1:Insert the boot password reset disk in the target PC and start it from the boot disk.
Step 2:When Windows Password Unlocker appears, select the user account you want to reset password of, and click "Reset" button. And the user password will be reset to blank in seconds.
Step 3:Click "Reboot" button to restart the computer and remove the inserted bootable disk during restarting.
Step 4:When the Windows 8 sign-in screen appears, select the user account you've just reset password of and log into it without password.
Windows Passwrod Unlocker is professionally designed to help all individuals and companies reset forgotten local admin, domain admin and other user passwords for Windows 7/Vista/XP/2008/2003/2000. The lost Windows 8 password recovery feature will be soon available.

If having or remembering the administrator password, the ways above are actually helpful. But if when you meet the situation that there is no or not remember administrator password in Windows 8, I think you can choose to use reset tools.

Windows Password Unlocker is a wonderful tool to reset windows password with simple steps.
I have ever used it to reset windows 7 password successfully.