freezer makes a clicking sound ,but won't get cold why?

i have a 4.5 cu. ft. upright freezer, model ewuf5w, it is manual defrost, it stopped working . it now makes a clicking sound, like it 's going to start, but it does not, the freezer is only two years old.a friend told me it might be the start relay switch ,located on the compresser. please help.