this is my new cheat code and it is very cool... :))
This cheat code is for Nintendo DS Hary potter and the half blood prince... :))
So enter this code at the Rewards menu to unlock the Castle gates Two-players dueling area.
So just enter this code, but very carefuly OK... :))
RIGHT,RIGHT,DOWN,DOWN,LEFT,RIGHT,LEFT,RIGHT,LEFT,RIGHT,START. :))
This is very cool cheat... :))
If you want some more cool cheats then just visit www.filetrip.net  
Hope this cheat helped you to beat the GAME.. :D

REMEMBER:Enter the very carefully... :))