Remove or Change password by command prompt

Change password by command prompt
Open Command prompt
Click start ...all programs ...accessories ...right click on command prompt and click Run as administrator

Note: Be carefully on this step!!!! When you type a password, it's not shown you what you type. 

look picture and follow step by step

c:\windows\system32>net users aunghla *

type a password for the user: 12345

type the password to confirm: 12345

after press enter