Neville and the Ghoul

I've don't play on this game much however... I've got some information here! This is a caption taken from BobBond0011's FAQ to the game!

In this room there is the Lumos Duo spellbook, just pick it up and a
firework will go off. Three Hinkypunks appear. You need to kill the
three Hinkypunks (lantern carrying ghosts) by using Lumos Duo on them at
close-quarters and then using Flipendo on each of them twice. Once you
kill all three another three come. It really does get exhausting. It
might help if you use a Wiggenweld Potion after the first lot. Now you
need to use Lumos Duo on the crystal ball and then move the mirror so
the beam of light hits the eye above the gate. The gate raises and you
can collect the House Points.

To defeat the Ghoul ...Shine Lumus on him until he goes into the gate .....

When the gouls have been released you need to shoot lumos at them until they turn solid then blast them twice with flipeno. Kill all four of them and more will come, do the same and they will all die. Then you need to shoot lumos at the mirror thing until it charges up. Then you turn the mirror around to face the eye on the wall above the trapdoor and the trapdoor will open.