This is my NAS server - the clamp is holding the SD card in place because the plastic card holder is broken.
It was happily serving away until it suddenly became inaccessible. It wouldn't reboot, and the problem turned out to be the card holder - at some point the thin plastic that holds the card in place had cracked and when I checked the seating of the card the broken plastic fell off. It's not a very rubust structure.
My first thought was to glue a piece of flat plastic across what is left of the holder, but the material seems to be impervious to super glue and there isn't enough of it to provide purchase for anything else. By using the clamp I have been able to check that the Pi is otherwise okay - it is - but that's obviously not a long-term solution. I might be able to glue the card in place but that would make future upgrades difficult.
I haven't been able to find a replacement card holder that matches the pinout (or even the number of pins) of the one on the Pi - if anyone can point me to a source, that will be very helpful. Removing the old one without damaging the board will be tricky, but if all else fails and I can find a replacement I'll give it a go.
The only other thing I've thought of is to glue a micro-sd adapter permanently in place and use micro-sd cards for the operating system.
If anyone has any other ideas, or knows where I can get a compatible replacement card holder, or has experienced a similar problem, your input would be much appreciated.