I tried to install Hunter 44110 programmable thermostat on a carrier hvac using the factory instruction. The ac will not work either compressor or fan. I tried to reinstall original carrier thermostat and ac will not run with it either. How do I correct the problem?

Did you disconnet the power to the unit before changing? If you didn't you either blew the transformer ot the Blade type fuse on the circuit board. Hpoefully it's a fuse. It will be either a 3 amp or 5 amp