My machine had stopped mid-cycle, and the pump simply hummed while the screen sat frozen. Pushing the on/off button just got stuck in "shutting down" mode, with the pump still buzzing. So I thought this might be an electrical issue. But there was a good bit of water still in the tank, and although the pump was humming, no water was moving.
The pump arrived two days later, and the repair was quite easy--especially with the aid of the videos on this site.