I was trying to connect the SD card that came with the 3DS to my computer to download some music. I stuck the SD card in the slot in the front of my computer, but I couldn't find the card anywhere to look through the files and copy some music on. This is really weird, because when I put it in the first time, the "AutoPlay" popped up for it and I could find it under "Computer" in the start menu. I know I didn't break the SD card because it still works on the 3DS. And, no, the "Locked" switch isn't on. The computer is a Dell XPS 420 and my OS is Windows Vista. I would appreciate it if someone who's more technologically versed than I am could possibly help me out. Thanks!

I'm an OSX user most of the time, so my Windows knowledge may be a bit rusty, but I believe any storage devices, including SD cards, should appear in the C:\ root folder, aka "Computer" or "My Computer". As you said, the computer did not detect the card when you put it in, nor did it appear in C:\ but you know the SD card works because you put it back in your 3DS and it was fine. So, it must be the computer. (Though, if possible, see if a different SD card will work, in which case something else is wrong). Anything could fix it. Start by blowing like you would with an N64. If that doesn't work, restart your computer (the simplest way to fix almost anything software-related). ((Hmm, Did you remember to internally eject the storage device?)) If THAT doesn't work, then there might be a hardware problem, meaning either your SD card actually is messed up, or the computer has stopped physically reading them. That last sentence is only an educated guess from my point of view though. Well, most of this was pretty much guessing. Again, I'm not as familiar with Windows as I used to be. Sorry if most of that paragraph was jumbled, and sorry if I stated the obvious.

You can find the SD Card drive in your "My Computer". If you can't find it even though it is in the slot, wipe off the dust from your SD Card using a tissue paper or cloth. If it still doesn't work, please send it back to the manufacturer.

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Marching Towards A New Era Of Hope After The Seven-Year Tribulation

Thanks, restarting the computer did work. But once I safely disconnected the card and took it out, the same problem happened when I tried to plug it back in. It's like the option to connect the card went away when I "safely removed" it. Anyway, I'll just download all the music I want at once so I don't have to keep restarting the computer.

I had an issue of the 3DS not finding the new SD card in it. It had save files on it and when I checked it was there, then when I took a picture it said there was no SD card. Went to check in the setting and it said none was inserted.
Though lately It's been fine for me so no troubles.