Had a power failure. My York modular air handler hasn't come back on since. Is there a reset switch, or could it be something else?

Confirming power supply to the system would be one of, if not the, first things to check after a power failure results in a problem. Got a voltmeter?

Can get one, but not until tomorrow

In the meantime, check any circuit breakers and/or fuses associated with the system. The primary control board may have a small, automotive-type fuse present.

If furnace was in a call for heat when power went out, excessive heat buildup(due to blower not running, because power was out) could have caused an auxiliary limit to trip. These limits are usually mounted on or near the blower housing. Should be a small red button in between the two wire connectors that can be pushed in to reset.