First you never add freon to a unit unless you are positive that it needs it.
Next are you sure that you are getting power to the unit, if you have a fuse box nearby, and if you have a voltage tester check the bottom of each fuse, you should get 240 volts. I you are getting 240 volts then you need to check the contactor to see if it is getting 24 volts to the coil of the contactor, if not you need to go to the furnace and check the voltage on the terminal strip. With the thermostat calling for cooling you need to check between the Y terminal and the and the C or Com. terminal you should get 24 volts if you do then you need to check the wiring from there to the outside unit, if you don't get 24 volts then you need to check the thermostat and the wiring from the terminal board and the thermostat.
Thanks Letmetellu
The freon was added after finding out it was empty. I had someone that I know to check it, he installs Units but can only do minor service repairs. I do know that he has checked to make sure there is power to and from it. The outside unit will start when the manual switch is pressed, but of course it does not stay on. Trying to avoid the high service costs at this time, just can't afford it.