You need to tell us more about your system. Do you have 2 air handlers, one downstairs and one upstairs. Does each air handler have an evaporator coil. Is each evaporator coil connected to its own condenser.
At the upstairs thermostat, set the FAN to ON, not AUTO. See if the blower works. If it doesn't, check the circuit breaker for the air handler. If the breakers are good, with the FAN set to ON, try and spin the blower squirrel cage and see if it will spin, even slowly. You may need to hold the blower compartment door switch closed so there's power to the blower motor.
If it spins slowly, then you need a new run capacitor, assuming an older, PSC motor.