Since the images you wish to recover were originally on the memory card, they can possibly be recovered using photo recovery software. (Your odds are better if you have not continued shooting with the card) . Connect the memory card so that it can be accessed like a removable hard drive on your computer. Once recovered and transferred to the computer you can format the card and it should be usable again.
For windows Try the Program Download at the link below. (This one will allow you to recover up to 1gb of photo files absolutely free and save them to a new folder on your hard drive. Copy and paste the link into your browser.
Make sure that before you open the program, after installing it, put the card in first. When you open the program, it will try to detect it when you click on "Media Recovery".
If unsuccessful try (The ones below have a charge to save the recovered files)
For Mac Try
http://www.cardrescue.com/ or http://www.stellarinfo.com
If the program is able to recover the photo files you will be given the option to purchase (usually around $40) the function that allows you to save and retain your photo files. Depending on how important these photos are, can determine if the cost is worth it.
Also, some retail camera shops and office supply stores offer Memory card recovery services if you do not feel comfortable running the process yourself.
Once the photos have been recovered, the memory card can be formatted using the camera's Format process and tested in the camera. Ultimately, a new card maybe the solution.
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