Central air fan won't turn

I have a Kenmore central air unit that is only 2 1/2 years old. It's
been working great and then we noticed that even though the unit will
kick on, the fan will not turn. Does anyone have any ideas? I've
read about a button that's on the unit that might need to be reset. I
can't find where that would be. Is there something I'm missing?
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