If user forgot administrator password in windows 7 then how can we retrieve that password?

Use Hiren's BootCD to recover any password. You can use Offline NT Password changer utility which  Supports all Windows from NT3.5 to Win8.1, also64 bit and Server versions (like2003,2008,2012). This CD is free to download and have so many useful tools.

ERD Commander would do it!

I have bookmarked the video tutorial that helped me find lost HP Windows7 admin password. it will also help you retrieve lost administrator password quickly!

by running in safe mode you made change and login again other wise cmos batter once off and on it vanish the password and now you again give the password else ctrl+alt+del it give you the portal there you found the hint if you know you can catch by hint as well