I've been having some problems with my SD card. It is a $40 2gb high speed card that I bought with my D40. The salesman at Barclay's Photo conned me into buying it, because he said it will prevent shutter lag. Well, turns out the low speed cards work just as well. Anyway, I've been having some problems with the card. I went to the Air and Space museum in Washington DC, and brought my D40. I took a lot of shots with the card, and halfway through the day a message popped up on my LCD that said "You need to format the card". So I turned the camera off, and tuned it back on. Same message. I turned the camera off, popped the card out, turned it back on, same message. So I figured I could resolve it on my computer when I processed it. When I put it in the computer, it said "You need to format the card." After that, I got so angry I yelled "I GOT YOUR FORMAT RIGHT HERE!" And snapped the card in half. Well, that last part isn't quite true, but it did upset me that I lost the majority of the day's photos. I've had a very similar problem before, however it didn't say "You need to format the card". It said something else, but I did randomly lost all of my photos. Twice. The first time after the different message was displayed (I forgot the message), I pressed the playback button and all of my photos said "file contains no image data" on all of my shots. After I scrolled through my recent photos, I started seeing a lot of photos that were deleted awhile ago. I thought that was an isolated incident, until today. Is there something defective about my card? Whats wrong?