The system is a Rheem, not that old... I noticed today that the house was not cooling, and that the larger of the two copper pipes was frozen over on the part inside the garage. I cleaned the filter but it wasn't really dirty, and let the pipe defrost by turning off the system. There is so much water dripping off the system. I checked to make sure the outside unit was running and it was. Why all the water, and why the frozen pipe? I'm in south FL and we have ahigh of 79 today.

Low air flow/defective indoor blower motor.
Low refrigerant charge.

System should be checked by a professional for corrections.

Turn the thermostat off for about 30-45 minutes and let anything defrost than may be frozen and then turn it back on... This may work, but if not then you should call an HVAC company for a service call...