I'm in CA and the AC went out. My poor wife, can't get anyone out until tomorrow. Air handler, nothing happening, compressor and fan, nothing happening. No clicks, noises, fans, no nothing.
Had her swap batteries in thermostat and reset breaker. Nothing.
Sounds like the control power transformer went out. If you have a meter you can check the pins on the wiring at the thermostat. Should have 24vac to ground on atleast 1 pin. If not, it's the transformer. Also, the transformers are fused, could check the fuse feeding the transformer and see if that fixes it.