The only other common issue I find is; if the sd card is 2gb, it's not recognized properly because of the card reader and or; the card is not formatted to fat 32. Other than that, ensure that the card works in other devices to rule out the possibility of it being a bad card. If it is 2gb or over 512Mb and if you get it to work in another device, try re-formatting it to fat 32, then check it in the computer that it is/was not working in. You should also try formatting it to FAT or FAT 16 if FAT 32 does not help, process of ellimination etc..