If the fan motor is running but the blade isn't spinning you can glue the fan blade back to the motor, use strong epoxy of some sort, theres lots of products that will get the job done.
Its pretty simple to do and a few of us have done it with write ups if you do a search for fan fix, broken fan, etc.
I fixed mine two years ago with a small screw through the blade into the square piece on the end of the motor and automotive goop and its still working fine.