Things You'll Need
Instructions
Navigate to "My computer" in Windows Explorer and right-click on your SD card. Select "Format" and choose FAT32 as the file system to format your SD card to. Click the "Quick Format" box and click "Start."
Download your choice of a USB loader program for the Wii. Copy the USB loader application files to a folder named "Apps" on your SD card. You may also need to copy other directories for the USB loader to the root of your SD card. See the specific installation instructions for the USB loader you choose.
Insert the SD card into your Wii and power it on by pressing the "Power" button. Go to the Homebrew Channel and browse until you find the USB loader you chose. Press "A" to launch the loader.
Insert the Wii game you would like to play from the USB thumb drive or external drive and press the "+" button to back up the Wii game to the USB thumb drive or external hard drive. Other loaders might require you press "A" on "Install Game." See the specific usage instructions for the USB loader you downloaded.