If you want to recover information, stop writing to the card and don't format the card.
There are free programs on the internet to recover deleted data or undeleted data on SD cards.
I paid for a program but there are free programs available on the internet.
The one thing you may need to buy is a card reader because recovery software often doesn't work with all the cameras out there.
There may be ways to recover files from a formatted hard drive but I don't want to make any false promises. Someone in tech may be able to better answer you.http://www.lc-tech.com/ http://www.infinadyne.com/flashretriever.html http://www.recovermyfiles.com/ http://www.recuva.com/