Harry Potter and the Chamber of Secrets Walkthrough
The Final Day - End of Game

Really, the sole purpose of this day is for you to go around finishing the other quests up. It's the next morning - Ron and Hermoine meet up with you. She's sad that exams are cancelled. They say the House Cup is about to be awarded.

Save here. You can go forward just to see what happens but it's pretty feeble. Sure enough (assuming you gave it even a half hearted attempt up until now) the House Cup goes to Gryffindor. It goes to you even without doing most of the other quests. You get a 2 second scene with them giving you the cup.

Then it jumps to a final scene with a narrator explaining that Harry tells them everything. It all had to do with loyalty, friendship and courage. And Harry was the Boy who Lived.

And then ... nothing. It just shows the regular main screen with new game - load game - options. And you think ... that's it?? So go restore from right before the final scene and do all of the card-collecting and quest-doing and flying around.

Harry Potter and the Chamber of Secrets Walkthrough, Tips and Techniques