Air Conditioning - Central AC/Heat

Turned on my AC through programmable two-year-old thermostat, Nada. Changed batteries in thermostat, still Nada. Tried "Fan"-Nada. Heat? Nada.
Went to breakers, turned off and reset, Nada.
Got my trusty little circuit checker, checked double switch breaker, and it lights up both 110v and 220V simultaneously. (I checked breaker by putting red probe to where one wire connects, and black to other connection.) Went to outside compressor, found disconnect box, it was installed OK.:wall:
Suggestions before I pay out small fortune for service?
Thanks in advance

Silly question but are you sure any emergency switches or service switches are turned on? Check the blower door on the furnace (presuming you have one) to verify it is on properly. If all is ok so far, use a volt meter to check for 24 volts AC from red on the thermostat to any other wire on the thermostat. If you have a gas furnace, many of them have a small automotive type fuse, usually either 3 or 5 amp.

Just got back in town, don't know if this will get picked up, but will try.
Don't have a volt meter, only a little circuit tester light.

hey sky dude, try a little experiment here. Take a piece of #18 insulated wire about 8 or 10 inches long, strip the ends back about 1/2 inch. Now I want you to apply the jumper at the thermostat from the red wire post to the yellow wire (only leave it on for a few secondsm and have someone outside by the unit to see if it kicks on. Now do the same thing from red wire to green wire except have someone near the inside blower to see if it kicks in. If the experiment makes both pieces work, replace your thermostat. If neither pieces will work, then carefully trace your thermostat wiring and inspect for broken or open wires. If you wish to check further you will have to go invest in a decent voltage meter. Please holler back at forum, I would be interested to see if you find the problem.