My Kenmore 70 Series Washing Machine (Model: 110.22712100) filled w/water, then won't agitate. It makes a loud humming sound but won't go to the next step.

The lid switch is new and works well.

Note that the machine did this humming at a different time in the laundry cycle, last week. I just moved back to an earlier part of the laundry cycle, and everything worked well,. for a week. Many successful laundry loads between the first hum and this latest hum

Nothing works now - just hums loudly. Help!