I have a 2GB kingston microSD card which is about 3 years old. I put it in a reader today in my Windows Vista computer, wrote a 32MB file onto it, safely removed it, and then tried to read it elsewhere. Nothing. Putting it back in vista it now says You need to format the disk in drive F: before you can use it.

What should I do? I have access to many computers and OSes if your recommendations need that. I would be very sad if I lost all the contents of the card. Most of the data is backed up, but there are a few things that aren't. :(

Doing a

# dd if=/dev/sdg of=~/tmp/sd.bin

gives me a 2 gig file, and grepping the file it seems like lots of my data is still there, how can I put it back together?