I had an issue with the SD card from our trail camera, caused by my finger trouble on the mouse pad thingy on a slow netbook pc. I downloaded/installed the recommended FREE SD Card Recovery programme suggested in post #2 which chuntered away for some minutes, declared 300 recoverable files but then said I had to buy something to actually recover the files.
I undeleted the FREE thingy and installed Recova. This found 168 deleted files but after trying only 84 could be recovered. It then listed 168 files in the new temporary directory and I'm not sure which it thinks it managed to fix and which it didn't. In the end, non of the recovered files would play.
I think that it may be a filename issue, all of the recovered files start with an underscore symbol. Removing this has made some files play.