The usual process of changing your password is very simple almost familiar to everyone I guess.
- Go to Start -> Setting -> Control Panel
- From the list select User Accounts and pick an account to change (its better if you log in as an administrator, only then you are allowed to change the password)
- Select change password
- Enter the old password, new passwords, new hint and enter
In the next restart you’ll be allowed to log in only with the new password. This process as you may see will ask for your old password to change your password. But you’re a human and many times humans tend to forget their passwords. What then? With this process you’re never going to be able to change the password.
- Start -> run
- Type ‘lusrmgr.msc’ (without quotes) and enter. (This will open Local User and Group management window. You can get this window by right clicking the ‘My Computer’ -> ‘Manage’ and from the Computer Management window, in the left pane under Computer Management’s System Tools select Local User and Group.)
- Under ‘Local Users and Groups(Local)’ select ‘Users’
- In the right pane right click the username whose password you want to reset
- Select ‘Set Password…’
- A warning dialog box will appear, read it carefully and click ‘Proceed’
- Enter and confirm the new password and click ‘OK’. A message will appear that your password has been changed.
You’ve successfully changed the password of an account (even administrator account) without even knowing the old password. Now, logoff and login with the username whose password you just changed. If you still can’t login, restart the system and then try again. Sneaky!!! Huh? 
