Basically, if you have an USB flash drive for password reset, you should be fine.
But, I'm sure you dun have that above so, let's start with this method.
If you are using laptop, turn on your laptop, press F8 before the windows loading screen is up.
Or, the old way which kinda spoil your laptop, remove the battery while the laptop is on and not plugged in with charger
You should be entering advanced boot options, which has safe mode or normal boot. Choose safe mode with command prompt.
If you done it correct, windows will load and go to the login screen. A command prompt should be appeared.
Type this,
net user and press Enter.
All the windows account will be listed on the screen.
Alright, now find your locked user and type this to change the password.
net user [LOCKED USERNAME] [password]
Ex:
net user killer150 killer150
After that, you can put in your new password and log in.