my zanussi washing mashine will not spin?

it fills up with water and makes the noises like it is washing but the drum is not moving. The belt is okay and i have checked for blockages, tried to just spin but also not working. the timer is counting down as usual but not sure why nothing is happening. it was making a crackling noise the last time it worked so wondering if possibly a chip inside not working. not an electrical fault as not tripping the electric please can anyone help