SIW has a "Secrets" section in its "Software" portion that will show credentials (username/password) that have been stored by Windows (not third-party applications) at one point.
It's a scary part of the program, since if you've ever saved your credentials, anybody who can install SIW on your PC can see all your usernames/passwords in just a few seconds.
If you can get into the various routers you use, you can usually see the Key in clear text with the click of a button.