bosch kgn34x00gb/01 fridge freezer. frost free type. freezer working ok fridge warm. have defrosted for 8 hrs now. stripped air vents but unable to remove cover from radiator area at top of freezer. how do i remove this? all screws have been removed but not budging, i do not want to force it for obvious reasons. when i turn appliance on i can hear compressor working and sound of fan although after a few mins there is a loud clonk sound??? any advice would be much appreciated!