Greetings and Welcome to TFP,
Either your motor has siezed up or you have a capacitor shorted/open.
If the impeller turns freely without any resistance, then you can look at the capacitor.
There are Youtube videos on how to check the capacitor. You can get the cheapest analog multimeter at Wal-Mart for testing.
If you are not comfortable testing electrical components, call someone to repair or replace.