Shredder not working

Though I only work with Fellowes shredders this sounds like a paper feed sensor issue. If your unit has a mechanical paper feed sensor you can try to jiggle it in and out to see if any paper may have become jammed behind switch. If the unit has an electronic sensor it may simply need to be cleaned with a Qtip dipped in rubbing alchohol. Sensor is usually located in the center of the paper feed opening.
If neither of these help your paper feed sensor or your pc board has gone bad and you will have to contact your manufacturer for further parts availability.