Brenda,
Hopefully this will be helpful. I got the Bissell Drive Belt Style 7/9/10/12 at Target which can be used on Bissell Upright Vacuums: Power Force Bagless 6594 Series, Cleanview II 3574/3576 Series, CleanView 3575/3590/8975/8990 Series, CleanView Power Trak 3591/3593/3594/6590 Series, PowerForce 3522 Series, PowerGlide 3545 Series
Unplug from electric outlet.
Remove drive belt Rotating Floor Brush from Vacuum by placing the handle in Low position and turn vacuum cleaner over so bottom side is up. Lift tab 1 and release the three latches in order 2-4 as marked. Lift the Brush Cover off. Grasp Rotating Floor Brush at both ends and lift to remove.
Grasp old drive belt and remove from Motor Pulley. Discard old Drive Belt.
Place new Drive Belt over Motor Pulley and stretch end over Rotating Floor Brush in the space between the bristles.
Place ends of Rotating Floor Brush down into slides on sides .
Turn Rotating Floor Brush by hand several times in the direction of the Motor Pulley. If properly installed, Drive Belt will center itself on Rotating Brush.
Reposition Brush Cover and snap back into place. Check to be sure all latches are secured.
Vacuum is ready to be used at this time.
Kelsey, January 2009