Make terrible noise when you click the lever to lover the back to use

That means that your brush is locking up. Lay the vacuum on its front and tilt the foot back. Remove the sole plate and make sure nothing is blocking brush from spinning. Then make sure that the end caps of the brush are facing up or toward the back of the unit which ever way you look at it. If thats all fine there is something that is jamming your clutch.This is harder to remove and will probably need to be replaced. They are not that expensive as you can probably get it for 60 bucks.