Once you have the regulator removed you can inspect it.

This regulator was removed because the window was moving very slowly. After removal it became obvious that it was bent, and it seems like the motor is weak as well. It will need to be repaired or replaced.

If you find your regulator is in similar shape, click here to review the rear power regulator repair guide.

If you removed your regulator to service the motor see the motor removal/replacement guide here.