Vincent Beron:"Re:dividsion by zero in winword"

[Robbert Xerox]

> So maybe we should actually check for the FAT

signature at buff[0x36] or
> buff[0x52] first, and then do the calculations if we

actually do find
> one of them.
>
> Changelog:
> Make sure we're really looking at a FAT before doing

some calculations
> based on the contents of the first sector of a

partition.

That doesn't solve the real issue, a FAT signature is
not a guarantee
that the rest of the block is valid, so we still need
to check these
values against zero. The code should not crash no
matter what garbage
the block contains.