stairs

Evening all. Relatively quick one for those knowledgeable in how staircases are/were built, I have no idea. Few pics below to show a 3x3 post "attached" to the staircase, wonder whether this would be removable or not? Or alternatively who I could go to for formal advice on it, what would need...

Hi My apologies for being ignorant about stairs and how to repair them. I have a carpeted set of steps leading to the bedrooms in the house (15 year old).Since yesterday,everytime someone is coming down the stairs, the very first step makes a louder,woody noise. What does it mean and what kind...