It's been a year or two since I set up a Netgear router (I assume that's what it is), but in my experience you don't need to use the CD to add wifi security. Login to the router using a web browser - the address is normally http://192.168.1.1 or http://192.168.0.1 (check the manual if these don't work). It'll take you to the Netgear login page and require the login details.
Name or admin is normally 'admin' and the password is 'password' (both without the quotes).
Once you're in click on the wifi section and it should be clear from there.
Edit: Not sure, but you might need to be connected via ethernet while you set it up.