Remove the access plate (a plastic frame over the brush roll) and check the brush and belt for damage. Be sure to clean off any debris on the brush. If brush will not turn by hand, you’ll need to replace the brush. You can do so by clicking here:
If the belt is broken, you can buy extras by clicking here: http://www.bissell.com/parts/?sc=part&productid=8899&partid=9762
If the brush still won’t turn, please take your vacuum to a technician. You can find your nearest BISSELL® Authorized Service Center by clicking http://www.bissell.com/support/product-support/service-centers/ or by calling 1-800-237-7691, available 24 hours a day.