Here are your parts
Replacement parts for FRG FFU2064DW2 | AppliancePartsPros.com

Here is the wiring diagram
http://manuals.frigidaire.com/p...df/StCloud/297010000.pdf

Could be that you were in a defrost cycle, the second time you checked it.
The evaporator fan goes off when in defrost.
The defrost timer looks like it is at the back by the compressor.
Rotate the cam to see if you can get the compressor to come on.
Remove the evaporator coil cover to see if it is a defrost problem.
Turn the temperature control to off the back on, sometimes thermostats can stick.

Your problem can be a number of things.
Compressor is toast
Compressor starter is toast
Evaporator is not defrosting
The thermostat is toast.

Here is a good link much of the fridge info also applies to a freezer.
http://www.applianceaid.com/repair-help.html

I unplugged the freezer for five hours and then plugged it back up. It works but does not get cold. I read on another thread that it might be the relay.
You say it works so if the compressor is running re: it is warm and you can feel it vibrating then it is probably not be the relay.
If the compressor is not running then it may be the relay. See Item 30 in Section 4, they call it a controller and it is listed at the bottom of the page as Item F30.

If the compressor is not starting it could also be that the thermostat's contacts are not close so the relay does not get any power.

Also I would not replace the relay without checking the compressor windings first with a meter. And checking that it is getting power from the thermostat.

Here is another good link on how to check things
Refrigerator Repair Guide: How To Fix a Refrigerator - ACME HOW TO.com