If formatting is the solution then you should try this application it has solved problems I've had with my memory cards, unless anyone else has any better application.
I've tried all those downloads as well... none work. I'm going to try a smaller SD card, maybe they sent me the wrong cards, though I ordered the SDHC It's the last thing to try at this point







Not to sound like a prick but I always wonder when I see these posts why didn't these people find this site and do research before purchasing the cards? I must have read at least a dozen reviews and researched which sites we're reliable for at least 2 weeks before making my first purchase back in 2008, which consequently are the same exact cards I still use today.