Hi there,
There are two types of 'Hacks' that can be carried out :
1) Modchip hack. By installing a modchip, you can play backups (copies of original) Wii games on your wii. The following thread will help you understand the process.
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2) Homebrew hack. Modchip is not required for this. Homebrew allows you to run third party applications and games generally not released for commercial purposes, such as GeeXbox media player, solitair and many many others. It also allows you to run emulators and games of older consoles such as NES, SNES, Sega Genesis, etc. This is all done thru the Homebrew Channel which itself requires to be installed using the Zelda Twilight Princess game save hack or if you have a Modchip and depending on your version of the wii drive type, you could either do this via a DVD iso install method or again via the Zelda TP Hack. See detailed guide for this here ->
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