I turned my AC off a couple of weeks ago - no problem. I tried to turn it to heat and turn it on and nothing happens. I tried the AC and it doesn't work either. It seems as though it isn't getting power. The power is on the gas is on and no breakers are tripped. Could it be that I need a new thermostat?

Need batteries?

Check on the furnace for a circuit board. Often there is either a 3 or 5 amp automotive type fuse. Have you had the furnace door off lately? If so, it may not be on correctly & failing to close a switch.