I have a 15 yr old 2 story home with a pine post and balluster stair railing that is free standing except at the top where it makes a 90 degree turn and is secured to the wall. I also have three active children. Several posts and ballusters are loose (likely due to the wood drying out and to little arms pulling on the posts) and I am concerned that they will become unsafe. I am assuming that the ballusters attach to the railing and stairs by dowels, and the posts are likely nailed or screwed from underneath. How can I repair/tighten them? By the way, the stairs to the basement are located immediately below. Thanks for any suggestions.

I purchased a set of door levers (dummy knobs) but I am having a hard time getting the small screw in. Is there a special tool I need? It's not shaped like a normal screw, but has a big hole (rather than a slot or cross) in it. Thanks in advance.