Freezer is not freezing

Freezer not freezing. No warning went off why??!
The compressor is hot is that my problem???

Here are your parts
http://www.appliancepartspros.com/partsearch/modelsearch.aspx?model=FFU21F5HWD

Here is a wiring diagram.
http://manuals.frigidaire.com/prodinfo_pdf/StCloud/297246001.pdf

Can you feel the compressor vibrating?
If yes then is the freezer fan running?
Check the frost/ice pattern on the evaporator/freezer coils.

If no you may want to unplug the unit, let the compressor cool down and then give it a try. If it does start up then check that the vents etc. for the machine compartment are clean.

Also if the compressor is not vibrating but is hot then I would check the compressor’s windings etc…
http://www.acmehowto.com/howto/appliance/refrigerator/refrigerator.php