With Windows 10, the easiest way to join a wireless network using its updated password is to simply "forget" the wireless network, and re-join it using the new password.
- Navigate to the Start > Settings (the gear icon) > Network & Internet.
- Tap on Wi-Fi.
- Tap on Manage known networks, located near the top of the page.
- Find the wireless network you'd like to forget, and tap on it.
- Tap the Forget button.
Now, simply join the wireless network as you would normally.
- For a hidden network, tap the wireless network icon in the system tray:
- Select Hidden Network from the list (near the bottom), enter the name of the network and click Next:
Note: both the name of the network, as well as the password, are case sensitive.
- Enter the password for the network and click Next.
- When/if asked if you'd like to discover network resources, click No.