Memory Card Mystery

I loaded a digital camera with a LExar SD card I had previously used in a Sony voice recorder. When I've done this at other times with other cameras, the camera added a DCIM folder and put its images there. But this time, when I transferred the card to my desktop PC's reader. it found only the Sony directories (the audio files had already been removed). But the images were on the card, as I saw when I put it back in the camera.

I then loaded the card into my Thinkpad's SD slot and easily copied the photos to the laptop. Then I formatted the card in the camera and copied the images back from the Thinkpad. The camera confirmed the images were there--but now my desktop PC can't detect the card at all!

Any suggestions?

You've done what I'd do so the suggestion exists that the card reader/slot in your Desktop has an issue. What I'd do next is shut down the Desktop, reach behind it and pull out the power cord, let set for a bit, plug it back in, start up and try the card again, sometimes things get a little out of whack and that process has usually worked for me. I do keep an inexpensive pocketable USB card reader on hand to try reading the card a different way, mine was $10 at local Wal*Mart a year ago.

Half the mystery solved itself: a software glitch had somehow led my PC to ignore the reader; rebooting fixed that.

HOWEVER, although I had reformatted this card in my camera and copied my photo files onto it, the reader on my desktop still showed only the Sony recorder folders, nothing from the camera!

Mystery deepens: With no SD card in the reader, This PC claims to see one, and clicking on it shows t he Sony file structure. Using Safely Remove to tell the PC it's not there yields a message that I can't do that because some Windows program is accessing it.

Attempting to format the phantom card, I get a message that I can't because it's being accessed by another program, then a message that formatting is complete. The SDHC still shows up in This PC, but now shows as empty.