Last night the units shut down. Nothing is running. I have reset the thermostat (White Rodgers 1F82-261), I have checked all the breakers and fuses, nothing is frozen. Does anybody have any ideas??

Most furnaces have a 3 or 5 amp automotive type fuse on the circuit board. If you can find it, check the fuse first. Do you have a volt meter & know how to use it?