Harry Potter and the Half-Blood Prince Cheats - Wii

Hogwarts Crest Bonuses
Collect crests to unlock various bonuses:

003 Crests - Two Player Dueling Pack 1: Draco & Luna.
008 Crests - More health in duels.
014 Crests - Two Player Dueling Pack 2: Training Ground Dueling Arena.
021 Crests - Dungbombs in prank boxes around Hogwarts.
029 Crests - Two Player Dueling Pack 2: Crabbe & Goyle.
038 Crests - Score boost in flying events.
048 Crests - Exploding Cauldrons in prank boxes around Hogwarts.
059 Crests - Two Player Dueling Pack 4: The Transfiguration Dueling Arena.
071 Crests - Even More health in duels.
084 Crests - Two Player Dueling Pack 5: Ginny & Hermione.
098 Crests - Love Potion in Potions Club.
113 Crests - Two Player Dueling Pack 4: Paved Courtyard Dueling Arena.
129 Crests - More mini-crests with each cast.

Easy Mini-Crests
You can get a large amount of Mini-Crests one time only, when you have used the Luck Potion and are making your way to Herbology. At this point, every time you use Diffindo to get the Mini-Crests to appear, you will get the full amount of Mini-Crests available, due to your luck. Get as many as possible at this point to help reach the 25,000 pieces goal.

Winning Fights and Duels
An easy way to win almost any fight or duel is to cast Levi Corpus or Petrificus Totalus. Then just charge your Stupefy until it chimes twice, then release it. It will result in a one hit victory until later in the game, then it will require two. Note: This does not work on Fenrir Greyback.

Use the following combo to defeat any enemy. Use Expelliarmus to knock them down. Charge up your Stupefy. While getting it charged, walk directly next to your dueling opponent. Fire your charged Stupefy for a one hit kil. This trick can give you 5 stars for the challenge very quickly and easily.