Recover stupid mistake

[Bruno Wolff III]

On Thu, May 27, 2010 at 13:32:51 +0100,
  Mike Martin <redtux1 at googlemail.com> wrote:
> Hi when I was trying (and failing) to get a bootable pen-drive, with
> the F13 live image I accidentally did the following
> 
> dd if=/dev/zero of=/dev/sdb bs=512 count=1
> 
> which returned nearly immediately and now I have no data on the disk.
> 
> The disk is 750 gig , of which about 400 is used. I am hoping that
> only the partition table is gone, if not is there any way to recover
> from my disaster

I believe that command just changed the first 512 bytes. If you know how
it was partitioned you can probably get things back by making a new
partition table.