Things You'll Need
Instructions
Plug the SD card into your computer's SD slot. If the computer does not have an SD slot, plug the SD card into the SD card reader, and insert the reader's USB cable into a USB socket on the computer instead.
Download a SNES DSi emulator program to the desktop of your computer. Double-click the file, to decompress it to a folder.
Click "Start." Select "Computer" from the pop-up menu. Click on "Devices" in the window that appears. Click once on the icon of the SD card, shown on the left side of the window.
Double-click the decompressed folder, to open it on the screen. Drag the two files from inside the folder -- SNEmulDS.nds and snemul.cfg -- onto the window to the right of the SD card's icon. Do nothing until the copy window has appeared and then disappeared from the screen.
Right-click inside the window to the right of the SD card's icon. Select "New folder" from the pop-up menu. Enter "SNES" into the text field of the window that appears. Click "OK." Drag a SNES ROM that has been legally acquired from its location on the hard drive onto the "SNES" folder. Do nothing until the copy window has appeared and then disappeared from the screen.
Right-click on the icon of the SD card. Select "Eject" from the pop-up menu. Close the window by clicking the red "X" in its upper right corner. Remove the SD card from the computer or from the SD card reader.
Insert the SD card into the corresponding slot on the DSi. Turn on the DSi. Navigate to the "Systems" folder. Select the "Devices" option. Highlight the "SNESmulDS" program. Press the "X" button to run the program, so that the SNES game can be played.