Medium strength Loctite available at Home Depot.Take the screws out completely and brush the threads clean with alcohol using an old toothbrush.Then place a drop of Loctite on them and torque them back in.Done for good.Loctite is not good for plastic parts though.Note that the medium strength Loctite is removable with excessive force .There is also a permanent Loctite but I wouldn't recommend it.That's what we use at work to install bolts.
Best of luck
George
Best of luck
George