Harry Potter 2 is protected with SafeDisc 2.8 and CD-checks.
In the regedit it points where the driver you installed the game from.
Try to change it to where you installed the game.
"C:\Program files\Ea Games\..."
Was an example.
Look at the HKEY_LOCAL_MACHINE\EA GAMES\Harry Potter 2\
or something like that.
and you might find a string call CD-Driver or something.
Change it to where you installed the game.
And test if that's works.
I got a good cracked .exe file And I think the main crack sites use that crack, but I also changed the reg. If that's doesn't help you. Please let me know..
One thing to, often the cracker team change the reg edit to \\ or .. or something like that.
Like a endles point or something. all I say try to change the CD-Driver just to "\\" or ... or "\" or something like that, and see if that works.