My DC200 had a similar issue just last week. During the dive, I started getting memory card "error" message whenever I turned the camera on. Sometimes the error message would go away and I would take some pictures, and sometimes I would get the error message and the camera would lock up again.
When I downloaded the memory card, every photo that I had "taken" in between the memory card errors was gone. They may not have ever been recorded. I scanned the memory card and found no errors on it. I cleared and formatted the memory card and put it back into the camera. Fingers crossed. If I get a repeat incident I will just replace the memory card next. The memory card is a few years old so I'm hoping that the card is the failure point.
Micro HD is a "permanent sealed" camera. No ports, no windows, no closures, no battery removal, no memory card slot, no nothing.
Everything is inside and unaccesable.