Probably a new capacitor. If the hum is from the fan then the cap is bad. If what you call a hum is really the compressor running, you need a new fan and capacitor. See if you can spin the fan blade while the power is off. If it is sticking, replace the fan motor. If the house is real hot, use a water hose and spray water on the coil. this can possibly get you cool again if the fan is dead.

Thanks for your help. I turned the A/C back on. I beleive the compressor is making the hummung sound. With the A/C off I can spin the fan, with the A/C on I cannot spin the fan. Like I said earlier fan motor was very hot. I will keep the A/C off until I can get it checked out. Is there a way I can check the capacitor? What can I expect to pay for a new one. What can I expect to pay someone to come out and replace it. I try to fix what I can. Thanks again for your help. Happy Fathers Day!

Another question. The fan motor was very hot, does that mean that it could be the fan motor is bad or could it still be the capacitor? or both? How much can I expect to spend on a fan motor? Thanks for your replies in advance!

If you cannot spin the motor while on, either the motor or capacitor is bad. Replace the cap. It is less than $10 for a single value cap. Copy the values on the side of the cap. If it has 3 poles, it is a dual cap, if only 2 poles it is a single pole cap. Look for the smaller value somewhere between 3-10 mfd. The voltage is probably 370vac. You can replace one side of the cap and leave the other side. You will need a common wire with 2 female push on spade connectors. or replace the entire dual cap. It will work the same either way.