I was at a friends last weekend and rebuilt his computer. Two new hard disks were to be used and everything to be reinstalled. When finished, the last step was to transfer his data from the old hard disk. I removed the backup hard disk from the mobile rack and in went the old one. When everything had been copied over, I asked "are you sure that nothing is hidden somewhere?". "I'm sure" was the answer and I deleted the single partition on the old hard disk. Luckily, before I had a chance to create a new partition, he said "well, not really, I forgot, is it too late?".
I thought it was too late, unless some recovery software was purchased but I spent the best part of an hour on the Internet searching for freeware. Finally, I found TestDisk which comes in two flavours, DOS and Windows. I used the Windows based version and managed to recover the deleted partition.
Just thought I'd let you know ...... ...... but I have no idea what would have happened if I had created a new partition and formated!