Your frind is probably right. Crack / damage may be internal, not showing outside.
If PC does not "see" it, there's not much to be done.
You could try - make sure contacts are clean. Blow out PC socket.
If PC /laptop, "see's" card, there is Software which might help.
If this does not help, card is dead!
To recover the deleted pictures, you need to connect your camera to your computer (usually via USB). . When you insert the card in the card reader, ((No Card Reader? Buy one fairly cheap at any local computer shop, or Amazon, BestBuy, Walmart. Connect the card reader to your computer,)) It will appear as a drive letter in "My Computer", which will allow software tool to access the data on the memory card.
If you have got your camera or card reader connected, you may download the picture recovery software
CardRecovery from the following URL:http://www.cardrecovery.com/download.asp
It's a small download and you may get it in less than two minutes. Run the downloaded executable file and follow the instruction to install it to your computer, then launch it. It has a wizard style interface and very easy to use.
Click Next on the welcome window, it will bring you to step 1. On step 1, you may specify the drive letter of your camera or card reader, as well other options including file type to retrieve, destination location to save the recovered pictures. Click next to step 2 and the scan will start. Depends on the capacity of your card, it may take several minutes for the software to fully scan your memory card. The found pictures during the scanning will be listed. You may preview the detected pictures as thumbnail on step 3, and choose the deleted pictures that you need. After that, click Next again and CardRecovery will save the selected pictures to the location you specified on step 1.
Your deleted pictures are recovered and back again. Can't be easier and faster!
1. Don't take more pictures on your memory card if you find you have deleted the pictures by mistake. Or it may cause overwriting and make them unrecoverable.
2. Use a USB 2.0 connection if available to connect your camera or card reader to your computer, it may make the scan much more faster than USB 1.x connection.