How To Change Password Of Windows 7 Administrator

Use the simple steps given below:
Go To Start Type cmd and right click on it and choose run as administrator it will ask to confirm choose yes

Their type net user and hit the enter key on keyboard

you will see their is something written like this
----------------------------------------------------------------------------------
Administrator                        BlackDeath                                           Guest              
The commnd completed successfully
c:\Windows\system32>


Now make changes like this 

----------------------------------------------------------------------------------
Administrator                        BlackDeath                                           Guest             
The commnd completed successfully
c:\Windows\system32>net user BLACKDEATH khjkf   

(NoTe: khjkf is the new PAssWoRD)
 
 hit the enter key and you are done.