I’m much more familiar with Android and iOS, but as far as I know there is no way to directly see the WiFi password on a Windows phone. However, if the PC is running Windows 8 with the same Microsoft OneDrive account as your phone, and the phone is running 8.1, it should sync the WiFi settings automatically. You might want to give that a try. Go to your app list on your phone, then Settings>Sync my settings. Make sure passwords syncing is turned on.