If the motor is turning make sure the drive belt is not loose or broken. Tighten or replace as needed.
 
  
** Walking belt moves, but there is a loud grinding noise.
 
Loosen the belt and see if the noise goes away, if it does you may have a bad front roller. Sometimes you can spray the bearing in the roller with a lubricant like WD40 and this will solve the problem, but you may need to replace the roller.
 
If the noise does not go away then the motor bearings are probably bad and you will have to replace the motor.
  
** Elevation does not work; unit will not go up or down or is stuck in the elevated mode.
 
Unplug the unit and check the elevation motor fuse, replace if necessary. Check the elevation system for broken chains or cables; make sure something hasn't gotten caught in the gears.
 
If your unit is equipped with limit switches for the up and down limits check them to be sure they are not engaged. These are usually little micro switches located around the elevation gears.
 
  ALWAYS LOOK FOR LOOSE OR BROKEN WIRES FOR ANY PROBLEM YOU ARE HAVING.
 
** You have power to the treadmill but the control panel does not work.
 
If your unit requires a key or a magnet make sure it is inserted correctly.
You may have a bad control panel, and you will need to replace it.

Use this link for the Full Treadmill Report

Treadmill Belts