I have a 98 Honda Civic DX. At times while driving, the entire electrical system will shut down, and the car's steering wheel will lock and the car will be unable to start. Minutes later, the electrical system will turn on again and the car will work, but it will incur the same problems later. I have a security system in my car which requires a fab to be near the ignition to start the car. The battery has been tested and it is in good condition. Any ideas?

Loose connection. Look at the fusable links.