Have you experienced a situation where you have to add a computer to your wireless network and cannot find the network security key? Windows 7, like previous versions of Windows, remembers (with your permission) the network security key when you first connect to a secure wireless network (Wi-Fi) protected by WEP, WPA or WPA2. This allows Windows to automatically log in to the Wi-Fi network when it starts.
To use this procedure to recover your network security key, you must have a computer already connected to your Wi-Fi network. Windows 7, unlike previous versions of Windows, allows you to easily see the network security key on the screen in plain text.
NOTE: Because the network security key is displayed in plain text, be very careful when and where you use this procedure. Make sure there is no one around by looking over your shoulder or looking at your screen.
See wireless network key
To start, select Control Panel in the Start menu.
If you have selected Categora as the Control Panel view, click Network and Internet.
In the Network and Internet window, click Network and Sharing Center.
If you have selected Small icons (or Large icons) as the Control Panel view, all the items available in the Control Panel will be available. Click on Network and Sharing Center.
In the Network and Sharing Center, click the Manage wireless networks link in the left pane.
Your wireless networks are listed in the Manage Wireless Networks window that uses window. Right click on the wireless network for which you want to see the network security key and select Properties in the popup menu.
The dialog box Properties of the wireless network for the chosen network appears. By default, the key in the network security key edit box is displayed as points instead of plain text. To view your network security key, select the Show characters check box so that there is a check mark in the box.
NOTE: To protect the security of your network, as soon as you have your security key, select the Show characters check box again so that there is no check mark in the box and your security key reappears as points.
Click OK to close the dialog box.
Again, be very careful when viewing your network security key in plain text to preserve the security of your network. Use this procedure only if you really need it. If you are using Windows 8 or Windows 10, the process is a bit different. Read my post on how to view your WiFi password saved in Windows 10. Enjoy it!