I'm assuming you can hear the compressor running. The following answer is based on the assumption that the compressor is running but the fan motor is not.

1. Make sure the motor is cooled down by shutting it off for a couple of hours.
2. Restart and immediately upon restart, try to spin the motor blade in it's normal direction.
After performing steps 1 & 2:
- if the motor starts spinning on it's own, it is one of two things: the capacitor or the bearings. If it is the bearings it is often-times difficult to start to spin the motor manually before it takes off. To check the bearings, turn all the power off to the unit....while holding the motor shaft, try to move it in all directions side-by-side (Not up & down). If the motor has any side-by-side movement, the bearings are bad.
- If the motor does not start spinning on it's own, does not feel difficult to turn at any time during the test and the bearings tested "okay", the problem is most likely electrical such as a wiring problem or failed relay. Check to ensure you have the proper voltage going to the motor. At this point, if you have limited experience with electrical motors and controls, it would be best to recruit help from a qualified service technician. Also, you want to look at your warranty on your unit. Many units today have a 5 year parts warranty; however, they have to be installed by a qualified A/C contractor for the parts warranty to be honored.

I hope this information helps you to better troubleshoot and understand your unit so that you can either continue to attempt the repair yourself or have a better idea of where to go for professional assistance. Good Luck! :-)