Top compartment of the freezer is not cold. The bottom section is still frozen, but no cold air is coming out of vents! It is a stand alone freezer Kelvinator/Electrolux FN430. What should we do??

The freezer not freezing, first inspect that is the fan in freezer running or not running.If the fan is not running then problem is with fan.Get the fan checked.Also many a times frost gets build up on the fan blades and that blocks the fan from running.In that case it has to be defrosted.-------- -------------- The actual cause of freezer not cold, is weak compressor.When the compressor gets weak, the freezer section will cool less.And then slowly --- slowly it will stop getting cooled and later on it will effect the fridge section cooling too.--------- READ the working procedure of your refrigerator.------- The working procedure of this unit is as follows: --- The compressor starts then it cools the freezer section. When the freezer reaches its cooling level the defrost cycle starts functioning. In this cycle the fan in the freezer section starts running and the cool air in the freezer section is passed to the fridge section and the fridge section gets cold. The air from freezer to refrigerator passes from the section, in that section the damper is located.------------ But as you mentioned that freezer not cooling this indicates problem with compressor.When compressor cools the freezer section then fridge section gets cold.If freezer section is not getting properly cold then fridge section will not cool properly/.So the problem relates to compressor.---------- In the compressor there is a refrigerant called FREON.With the help of this Freon the compressor cools the freezer section.Freon is a gaseous type cooling agent.The compressor will stop cooling when coolant gets leaked from its chamber.--------- Again recharging the Freon is possible, but the cost for that recharging is approx the cost of new compressor.So its always advisable to get compressor replaced.Because new compressor has warranty for few years.------------------ You can get required parts from from online sites like: --- www.repairclinic.com or from searspartsdirect online site. ----------- But before you get replaced any thing, first try reset procedure, its called defrost reset procedure:----

The manual defrost reset procedure is as follows : ----
First unplug the unit from main power outlet. Then empty whole unit completely. Then keep both the doors open. Wait for 24 hours. All the ice collected on the coils and in the freezer section will get melted. Clean the water from the sections. Then Connect the power cord of the unit to main power outlet after 24 hours/.Then set the temperature to normal in both fridge and freezer section. Then check, if the same problem is noticed, then its compressor issue and needs to be inspected.--------- This will help.Thanks.Helpmech.