I have had a home network for several years. When I initially set it up, I did not set it up with a password key. Now I want to go back and make it secure and put a password key on it. How do I do this? Help!

is your network connected to a router?

There's really nothing to protect in a home network that is accessable only by you and other members of the family with your permission. If you have a wireless router, that's another thing. Follow the instructions HERE to set up security for wireless.