My heat pumped stopped after hearing pop in hvac closet. Checked fuses inside. Pressed reset button outside. Any suggestions?

Pop more than likely sounds like a transformer that has popped or a wire that has grounded out. Not sure if you had any electrical smell that went along with it but that is what it sounds like. The pop could have been on the 240 or 120 volt side and thus your 5amp fuse for the 24v side that powers the thermostat etc might still be intact. If you can pull power to the air handler or throw the breaker and open the cabinet you shoud be able to smell the electrical residue or see a clear burn mark.

Good luck