It is possible that the card just packed it in, as storage devices will inevitably do. I had a similar problem once when using my laptop. It was purring like a kitten one second, then out of the blue the whole OS failed to respond (totally, as in not even the mouse would move). Several scans (quick and in depth scans) on the HDD determined it had failed. that's how suddenly storage devices can fail. It doesn't have to happen on a write cycle either (i.e. file system corruption). There are other causes of failure.

Hopefully, for your sake, this is not the case. Try Piriform Recuva to attempt to recover the photos. I've used it, and it's pretty good. Failing that, they may be gone for good.

Good luck, I hope you can at least get the photos back

It is possible that the card just packed it in, as storage devices will inevitably do. I had a similar problem once when using my laptop. It was purring like a kitten one second, then out of the blue the whole OS failed to respond (totally, as in not even the mouse would move). Several scans (quick and in-depth scans) on the HDD determined it had failed – that's how suddenly storage devices can fail. It doesn't have to happen on a write cycle either (i.e., file system corruption). There are other causes of failure.

Hopefully, for your sake, this is not the case. Try Piriform Recuva to attempt to recover the photos. I've used it, and it's pretty good. Failing that, they may be gone for good.