Product review (5 stars): First thing you should replace if AC not working.
Much cheaper than having an AC guy come out.  Have a few on hand for future.  this capacitor is the number one thing that gets burned out on an ac unit.  After about 2-3 years it will give out.  My neighbor had someone come out and replace and it cost $75.  It was very simple to replace.  You just need the correct power, you don't need the exact same shape.  If it is slightly thicker or thinner than current one, just use zip tie.

If you fan is not spiining, good chance this is your problem...could also be motor....but most of the time this will fix the problem.