Our Kenmore chest freezer Model 253.16342102 will

Our Kenmore chest freezer Model 253.16342102 will not freeze the food inside it anymore.
The blue defrost indicator is not covered with ice. In fact the freezer is empty now since all the food was thawing out.

The freezer will power on but will not freeze the food inside = pump operates & power light illuminates.

I have unplugged the freezer from the power receptacle for 5 hours and then plugged it back in, but this did not resolve this issue either.

I have removed the service panel from the Left Hand Bottom side of the freezer and can not find anything wrong. The black canister / pump in this area makes a rattling sound, but that is it.

The freezer will power on and off when the power/temperature control knob is rotated from the on to off position

This freezer has worked great this past year then overnight it stopped freezing the food inside.

We purchased this freezer new from Sears on August 28th, 2008 and just our luck it is just past the 1 year warranty period.

What is wr