Inside Hogwarts (2nd)
Dungeon (Potions & Slytherin Common Room)
When in the dungeon, right after you get off of the stairs, run past Snapes classroom until you pass two suits of armor. Cast at the first up-side-down T window on the right, which has a gargoyle behind it. Once you have cast Lumos run towards the grate, which is on your left if you’re facing the gargoyle.
When you are in the room with the door to the Slytherin common room cast at the 2nd up-side-down T window on the right. Then cast at the gargoyle behind it and run to the common room door. The wood beside the door should be illuminated and you will have to cast Deffindo to break the rope. (The floor will drop, so don’t freak out.)
Fourth Floor (Bathroom, Transfiguration, & Charms)
In the bathroom cast at the toilets that have no door. They will give beans almost every time you go in after getting out of the game.
Go down the hall towards the bathroom and stop before the wall that had writing in blood on it. Turn right and cast at the wall (you may have to move to your right to look at the wall). This will open a secret room.
Fifth Floor (Dumbledore & Defence Against the Dark Arts)
Cast at symbols on the wall and suits of armor to find the secrects on this floor.
When you are in the Defense Against the Dark Arts classroom (not during class) cast at red bottles, chest, and suits of armor. If you cast at the hanging dinosaur skeleton you won’t find beans.
Sixth Floor (Infirmery)
In the Infirmery, cast at each of the four pictures in the main room to unlock a secret in the floor in the middle of the room.
When you walk through the main room of the Infirmery, turn left and you will see a Lumos gargoyle. Cast at this, then turn completely around and go a short way down the stairs. If you look up you will see an illuminated block that you can jump on to reach a chest.
After walking through the main room of the Infirmery, when standing at the top of the stairs that lead into Madame Pomfrey’s office, jump on the square, dark carpet. Now walk down either side of the stairs. You will find a Spongify pad on the floor in about the middle of the room, in front of the white medicine cabinets. Use this to access the room that opens in the ceiling.
Second Floor (Gryffindor Common Room & House Point Ceremony Room)
Be sure and cast at all mirrors, suits of armor, symbols on the wall, and statues. All of the secrets have to do with these things.
When standing at the top of the Grand Staircase with your back to the stairs, turn left, then turn left again immediately. This will lead you to the House Point Ceremony room. In the antechamber before this room, turn left and you will see a symbol. Cast at this symbol to open a secret room.