Let's make it quick: I deleted my microSD's system file, that much is obvious, it was a file with "trash" string on it, along with it there's a folder named trash0000 and another folder (apparently I forgot), they never appeared before and they're hidden , so I thought it was a virus, even worse when my friend told me that his computer is being struck by a virus (I was copying CoD 4 from him), so without a doubt I deleted it. Truns out it was a system file, now my microSD won't boot! I inserted my microSD reader into a USB port and it worked fine. I inserted my microSD to my NDS and it worked fine, since R4 doesn't have to read those files, but now I can't transfer any data to and from my microSD! I'm using Windows Vista, if that's any help, maybe in older versions of WIndows my microSD will boot? So I can format it? What about Mac?