Shoutbox

I think it's highly unlikely that even Microsoft would do away with FAT32 supp... actually no it's nearly certain they didn't, most USB flash sticks use FAT/32.

Is B: an actual drive or another partition?

I've never seen a hard drive become corrupted in this way on its own (unlike bad sectors, which can happen for no reason except extensive use), I'd recommend trying out Knoppix or another program which should let you see if the filesystem structure is still intact.

If it isn't... there are data recovery programs out there but they're far from cheap.