Have you faced a situation where you need to add a computer to a wireless network, but you cannot find the network security key? Windows 7, like previous versions of Windows, remembers (with your permission) the network security key the first time you connect to a WEP, WPA, or WPA2 secured wireless (Wi-Fi) network. This allows Windows to automatically join the Wi-Fi network at startup.
To use this procedure to recover the network security key, you must have a computer already connected to your Wi-Fi network. Windows 7, unlike previous versions of Windows, makes it fairly easy to view your Network Security Key on the screen in plain text.
NOTE. Since the network security key will appear in plain text, be very careful when and where you use this procedure. Make sure no one around you is looking over your shoulder or looking at the screen.
View the wireless network key
First, select “Control Panel” from the “Start” menu.
If you selected a category as your control panel, click Network and Internet.
In the “Network and Internet” window, click “Network and Sharing Center.”
If you selected Small Icons (or Large Icons) as the Control Panel view, all available items in the Control Panel will be available. Click 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 your wireless networks in use window. Right-click the wireless network for which you want to view the network security key and choose Properties from the pop-up menu.
The Wireless Properties dialog box for the selected network opens. By default, the key in the Network Security Key edit box is displayed as dots rather than plain text. To view the network security key, select the Show Symbols check box so that the box is checked.
NOTE. To protect the security of your network, once you have the security key, select the Show Symbols checkbox again so that the box is unchecked and your security key is displayed as dots again.
Click OK to close the dialog box.
Again, be very careful when viewing your network security key in plain text to keep your network secure. Use this procedure only if absolutely necessary. If you’re using Windows 8 or Windows 10, the process is slightly different. Read my post on How to View Saved WiFi Password in Windows 10. Enjoy!