Things You'll Need
Instructions
Banner bricked Wii
Visit the Wiibrew website (see Resources) and click on "Download" on the right side of the page. This will save the Any Title Deleter software to your computer. Extract the software and insert a formatted SD card into your computer. Move the Any Title Deleter to the "Apps" folder you should have on the root of your SD card already from installing the Homebrew Channel. If you do not, right-click in the root of the SD card menu and scroll down to the option "New Folder" and click on it. Rename the folder to "Apps."
Remove the SD card from your computer and put it in your Wii console. Press and hold down the "Reset" button on the front of the Wii while pressing the "Power" button. This will boot your Wii into the Preloader or Priiloader menu. A banner bricked Wii means that there was a WAD channel installed on the Wii that is not set to run with the Wii system menu correctly. A Wii that is banner bricked will not be able to load the Wii system menu.
Press "A" on the Homebrew Channel to load it and look for the Any Title Deleter. Once you find it, press "A" on the channel to load it. Locate the channel that you installed that caused errors and delete it with the Any Title Deleter.
Theme bricked Wii
Navigate to the Wiibrew website for the NUS Downloader (see Resources 2) and click on "Download" on the right side of the page. Once the download finishes, extract it and install it on your computer.
Open the NUS Downloader software and click on "Pack->WAD" to save the WAD file so that it can be loaded onto the Wii. Click on the "Database" button and click on the "System menu" link, afterwards you will be presented with a new sub menu list. Look through the available options until you find your Wii system menu and click on it. Click on the "Start NUS Download!" button to download your Wii system menu. Extract the WAD file.
Insert a formatted SD card into your computer. Create a new folder on the root of your SD card and name it "WAD." Place the WAD file of your system menu into the folder.
Visit the Gaming Network website (see Resources 3) and click on the "Download!" link about midway down the page to download the WAD manager. Extract the download and place it into the "Apps" folder. Once you have placed the WAD Manager into the "Apps" folder, remove your SD card from the computer.
Place the SD card into the Wii system and hold down the "Reset" button while you press the "Power" button to turn the Wii on. Access the Homebrew Channel by pressing "A" on it and cycle through the apps until you find the "WAD Manager v1.4" and press "A" on it to launch it.
Select the "IOS36" or "IOS249" option by pressing "A" and cycle to "Install WAD" and press "A." Cycle to "Install from SD card" and press "A." Cycle to the Wii system menu WAD file and press "A" on it to restore your Wii menu from a bad installed theme.
Full bricked Wii
Open the NUS Downloader program and click on "Pack->WAD" to save the WAD file so that it can be loaded onto the Wii. Click on the "Database" button and retrieve important system files you deleted. These can be system menu IOS's or even the system menu. If you accidentally delete these files, you will cause a full bricked Wii.
Click on the specific files that you deleted on your Wii to download them onto your computer. You will have to reinstall the files onto your Wii to regain functionality.
Put the SD card into your computer. Place the files you deleted into the "WAD" folder on the SD card and remove the SD card from the computer afterwards.
Place the SD card into the Wii system and hold down the "Reset" button while you press the "Power" button to turn the Wii on. Access the Homebrew Channel by pressing "A" on it and cycle through the apps until you find the "WAD Manager v1.4" and press "A" on it to launch it.
Select the "IOS36" or "IOS249" option by pressing "A" and cycle to "Install WAD" and press "A." Cycle to "Install from SD card" and press "A." Cycle to the WAD files and press "A" on them to re-install them and repair your bricked Wii.