stan hithersay

This past week, my 77 280z totally lost power when I try to start her. When I turn on the key, the starter does not engage, the voltage drops on the interior guage. I have a new battery, altenator is testing ok, and I have replaced the voltage regulator in the past 2 months, and everything has been fine. Tests I have done: I cleaned battery cable connections at battery as well as at the starter connection. Voltage tested these connections and get 12.45 volts. Also voltage tested each of the fusible link wires (which read 0.00 when I move the wire around, so I believe these are good.). Can someone please give me some advise as to what to test next. Want to get "Zena" running again. Thanks, Stan in Dallas