On a Windows PC or laptop:
1) Click on your control panel.
2) Click on Network and Internet.
3) Click on Network and Sharing Centre.
4) Find your wifi network and click on it.
5) A Wireless Network Properties dialogue box will appear. Click on the Security tab.
6) Your password is located in the network security field. CHeck the 'show characters' box underneath to view your password.
On a Mac:
1) Type Keychain Access into Spotlight search at the top-right menu bar.
2) Search for your wifi network and double click on it.
3) A dialogue box will appear. Check the 'show password' box. You will be asked to confirm your administrator user name and password.
4) Your wifi password should appear in the field next to 'show password'.