Have you ever wanted to know password that was entered on your computers? Here is and easy way, no need to install. Everything is build-in windows to provide you this information.
Open Command Prompt (start → run → cmd)
netsh wlan show profile
You'll get a list of Wifi's, that you have ever connected. To get password of particular wifi, type following command:
netsh wlan show profile MyWifiName key=clear
just change MyWifiName to something from your list. In “Security settings” group, Attribute “Key Content” you'll see a password saved in your OS.