Sandisk SD card I/O error

Can anyone help? A friend of mine recently bought a 1GB Sandisk SD card for his digital camera. When he put the card (with photos on it) into a card reader to view on his PC, a few photos appeared on screen briefly then dissapeared. Now when the SD card is put in the card reader (or a different reader built in to a laptop) the pc is unable to view any photos on it.

An “I/O error” message is displayed

The camera can’t access it either. We tried using “O&O disk recovery” program to rescue the photos, but this program didn’t even recognise the SD card at all.

Would be very grateful if anyone has some advice on either how to rescue the photos, fix the card or what might have caused the problem in the first place?

Thanks