Diagnosis
The drive belt has broken or come off the motor pulley. This is a frequent failure point if hair wraps around the brush roll ends and seizes it.
How to Fix It
Unplug the vacuum. Remove the floorhead. Turn it over. Use a coin to turn the four latches to unlock the bottom cover. Remove the cover. You will see the brush roll and belt. Remove any hair from the brush roll ends. Check the belt. If it is broken or missing, replace it with part #160-4150, the official belt for this model.
If That Didn't Work
With the floorhead removed and the vacuum turned on (wand mode), listen at the hose connector on the floorhead. You should hear the motor engaging. If silent, the electrical contacts in the wand or floorhead connector are dirty or bent, preventing power from reaching the floorhead motor.
Heads Up
When reinstalling the brush roll, ensure the belt is correctly seated on the small motor pulley before snapping the brush roll into place. An improperly seated belt will shred immediately.