If your roller doesn't turn after replacing the clutch, pull the roller brush back out of the vacuum. Then pull off the end caps and clean out any debris that has accumulated inside the bearing area there. After putting the ends back on, make sure that they are lined back up so that they face the same way on both sides. Also check to make sure that the brush spins freely when held by the ends. If you still have problems, make sure that the knob is set to "carpet".