Things You'll Need
Instructions
Download the latest version of Nintendo's Wi-Fi USB Connector software at the Nintendo websites support page (see "Resources"). Choose the software you wish to install and click "Save." Save the file to your desktop.
Right-click on the file after it downloads and click on "Extract All." Click "Next" twice and "Finish" to place the opened file on your desktop. Click on the "NintendoWFCReg" file and choose "Setup.exe" to install.
Insert the USB adapter into your computer's USB port and wait for it to be recognized.
Double-click on the Nintendo Wi-Fi connection logo in your system tray to bring up the program.
Turn on your Nintendo DSi and tap on "Nintendo Wi-Fi Connection Settings." Tap "OK" to continue.
Wait for a window to appear on your PC that asks if you want to grant permission for the DSi to connect to the Internet. Click "Grant Permission to Connect" and the DSi will connect to your Wi-Fi.