If engine will turn over, change plug. If its "stuck" you might be able to pull plug, fill what you can of cyl with like ATF or some light weight oil and let it soak for awhile. Try to flush the fuel lines and get pre-mix up to carb and a new plug and see if it will run. If the rings/piston are bad, I would say chance are it will cost more in parts than what its worth. I'm actually thinking if mine dies going cordless. Home Depot has a cordless job (I think its Bosch or Ryobi) that uses the same batteries as the drill saw etc.