You say that you got someone in to check the lid & out of balance switch. Why did they not check the whole machine & find the problem for you? The only thing you can check yourself is if the bowl & agitator will turn freely by hand when empty. If it is tight then the bearings may be seizing up but you would of noticed it getting very noisy when spinning before now. If it is free to turn then the motor, RPS sensor or the actual motor controller is the fault. You need the correct test equipment to check them. I would suggest you call someone out to repair it for you.
Lincoln Appliance NZ, August 2009