First you need to disconnect all power. Try spinning the fan blade, if it spins freely, then try moving the shaft from side to side to see if there's any side play. If not then the bearings are OK. If there seems to be some drag when your spinning the blade, then the bearings are bad and the motor needs replaced. Then you need to have the capacitor checked, a lot of times your parts house will check it for you. If those are OK, then very carefully turn the power back on and check to see if you are getting the proper voltage to the motor terminals. if you have the proper volts and every thing checks OK, then, you need to replace the motor.
Answers & Comments
First you need to disconnect all power. Try spinning the fan blade, if it spins freely, then try moving the shaft from side to side to see if there's any side play. If not then the bearings are OK. If there seems to be some drag when your spinning the blade, then the bearings are bad and the motor needs replaced. Then you need to have the capacitor checked, a lot of times your parts house will check it for you. If those are OK, then very carefully turn the power back on and check to see if you are getting the proper voltage to the motor terminals. if you have the proper volts and every thing checks OK, then, you need to replace the motor.