I have a frididgare freezer my freezer is not staying cold but the fan is continuing running. When I took the back off the coil is completely covered in frost can you help me

You need to totally defrost the back of the unit where the coils are located and get rid of all the build up. If your feeezer is kept in a room where there is a lot of humidity this could be the culprit (the humidity). It may run fine and dandy after being defrosted and it might not. The only way to tell if the frost build up caused the unit to malfunciton would be to turn it off and totally defrost the outside coils. There are not too many moving parts in a deep freezer to go bad. Let's hope that the humidity did it and you don't have a freon leak somewhere.

If this is a self defrosting model one of the switches for the defroster went bad and needs to be changed out. If it is not a self defrosting model you should be okay.