If it won't turn because the worm gear/shafts are frozen there's a small oil hole on the crankshaft at its far end, just before it goes into the housing. Try tipping the saw on end (backside on the ground) and spraying some brake-free or other good solvent/cleaner/lubricant into the oil hole. Fill it repeatedly until it doesn't take any more without running out. Let it sit for a day or two and it should come free. Replace the solvent with synthetic motor oil. Worked like a charm for me.