I really don't know how I would google for this problem seeing as how I'm not quite sure what it is, so it's up to you guys.

Recently I bought a 1GB MicroSD card for my R4(A Nintendo DS card that modifies the DS so it can play downloaded games). I've been using it on a everyday basis and I've put gmae, mp3 and picture files on it. I was just using it with the R4 a few moments ago and it froze up. I turned off the DS then turned it back on, and I got a message that the MicroSD was empty. I removed the SD, plugged it into my computer, opened the file and inside it was a strange file, and other then that it was empty. To test it, I tried making a text file in the card, but it said there was no space. After this, a bunch of files showed up, some of them appearing to be hidden files, all of them having nonsense names including characters my computer didn't understand. I could not delete these files, move these files, or rename these files. I'm guessing some software I put onto it corrupted the card and I'm looking to you guys for some confirmation or a way to fix it.

ALSO; I have a feeling that the fact that I recently turned on my firewall may have a hand in this, however I turned on my firewall after the card was removed.

HALP?